Using Bondo Glazing and Spot Putty

[BigRiJoe]

I really have not liked the results I got using Elmer's Fill 'N Finish to eliminate the body tube spirals. I bought a tube of the Bondo Glazing and spot putty; any tips on how to best use it eliminate spirals?

 

[bubamech]

Although I have not used it on the spirals, I have used it on the space between the transition and the body tube of two bull pups with great results. It takes longer to dry and is a bit tougher to sand, but left me a beautiful finish. Good luck with the spirals, I will stick with Elmers for those.

 

[sodmeister]

I use Bondo Spot Putty exclusively on spirals and areas that need filling.It dries quickly and sands very easily, although it does smell badly, but the VOCs are what makes it apply easily and dry fast ,so it`s a trade off......I like it...smells like rockets !!

On deeper spirals ,you may need to apply it a second time ,as it does shrink at bit as the carriers evaporate leaving the Talc behind (yup ,basically just talcum powder in a carrier)

I can easily do a 4" body tube 48" long in 15 minutes and ready for sanding in a half hour ,but of course ,temperature and how thick you apply it will determine this.

I take the tube ,squeeze out a bit (1/2" long) and use a stainless steel square tip spatula (craft store ,woodworking supply,Mickaels) and work it along the spiral in one motion.It`s like drywall taping and mudding ,DON`T over work it ,do it once and move on.

I then take the spatula and scrape off the excess Putty from both sides of the spiral /seam ,careful not to scrape or touch the area that was filled ,and wipe the spatula blade off on a paper towel (I take a large piece of paper towel and tape it down near the area where I`m filling ,so it only takes one hand to do the job of cleaning the blade)

The more excess putty you remove now ,the less sanding you do later.

After you`re done ,examine the spirals ,you`ll be able to tell or even feel if the spirals are filled ,if not ,repeat the process ***** NO need to sand first ,just re-apply over the same areas ****

When it`s all good and you are pleased ,sand down with 180 grit (nice and easy) then follow up with 220 and dust off (a TACK CLOTH works best for this after getting the major dust off with a Shop Vac or similar) and prime with a good high solids primer and paint.

Works on all types of body tube material ,and thinned down with lacquer thinner and painted on wood ,works great and does not warp like water based stuff.

There you go....easy...peasy

Cheers

Paul T

 

[Andy Greene]

My brother showed me a product called " Icing " really nice to work with and sand pretty easy. Its kinda pricey , but worth it.

Andy

 

[pepe]

Follow Sodmeister's directions and you'll love it! .I just switched over from Elmer's wood filler and the difference is obvious. Less sanding and better results.

 

[luke strawwalker]

Agree... sodmeister nailed it...

One thing-- if you ever gas up at Walmart-- grab a handful of the old gas cards people leave up there when they're empty on top of the pumps... those work GREAT as "mini-spatulas" for spreading and leveling the filler in the spirals, and scraping off the excess...

Later! OL JR

 

[Marc_G]

I'm in agreement with all of Paul's notes but let me add one more:

I find that pre-spraying the body tube with a lightish coat of filler primer really helps me with this kind of spiral-filling job. I mask off where the glue joints will be for the fins, then spray the tube with Rustoleum auto filler primer (gray stuff). After that dries you will know EXACTLY where on the tube you need to fill (spirals and any other imperfections will stand out). Also, as you are sanding your spot putty, if you over-sand the adjacent areas the gray primer will wear away and you will see it before you cut too deep.

Invest in some good sanding sponges-- 220 and 320 will give you a nice shiny smooth tube. They conform to the curve well, so don't leave flat spots or streaks.

When I want a first class result, this has worked well for me.

I've also heard folks first spray a white or black lacquer (again, fin areas masked off...). These dry hard and let you bear down more on the sandpaper as it takes more effort to cut through a lacquer that has hardened up. Another benefit is that a lacquer is non-porous and thus water won't easily soak through. If you are damp-sanding a primer coat later, water will go right through the primer and soften the paper tube, but would be stopped by a layer of lacquer. Haven't tried this but plan to sometime soon.

Marc

 

[AfterBurners]

I use Bondo Spot Putty exclusively on spirals and areas that need filling.It dries quickly and sands very easily, although it does smell badly, but the VOCs are what makes it apply easily and dry fast ,so it`s a trade off......I like it...smells like rockets !!

On deeper spirals ,you may need to apply it a second time ,as it does shrink at bit as the carriers evaporate leaving the Talc behind (yup ,basically just talcum powder in a carrier)

I can easily do a 4" body tube 48" long in 15 minutes and ready for sanding in a half hour ,but of course ,temperature and how thick you apply it will determine this.

I take the tube ,squeeze out a bit (1/2" long) and use a stainless steel square tip spatula (craft store ,woodworking supply,Mickaels) and work it along the spiral in one motion.It`s like drywall taping and mudding ,DON`T over work it ,do it once and move on.

I then take the spatula and scrape off the excess Putty from both sides of the spiral /seam ,careful not to scrape or touch the area that was filled ,and wipe the spatula blade off on a paper towel (I take a large piece of paper towel and tape it down near the area where I`m filling ,so it only takes one hand to do the job of cleaning the blade)

The more excess putty you remove now ,the less sanding you do later.

After you`re done ,examine the spirals ,you`ll be able to tell or even feel if the spirals are filled ,if not ,repeat the process ***** NO need to sand first ,just re-apply over the same areas ****

When it`s all good and you are pleased ,sand down with 180 grit (nice and easy) then follow up with 220 and dust off (a TACK CLOTH works best for this after getting the major dust off with a Shop Vac or similar) and prime with a good high solids primer and paint.

Works on all types of body tube material ,and thinned down with lacquer thinner and painted on wood ,works great and does not warp like water based stuff.

There you go....easy...peasy

Cheers

Paul T

Paul

You can use it right from the tube without mixing or cutting it with anything. It's already the consistency?? Doesn't Wally World sell it?? I like to try it sometime and see how it works.

 

[AfterBurners]

I'm in agreement with all of Paul's notes but let me add one more:

I find that pre-spraying the body tube with a lightish coat of filler primer really helps me with this kind of spiral-filling job. I mask off where the glue joints will be for the fins, then spray the tube with Rustoleum auto filler primer (gray stuff). After that dries you will know EXACTLY where on the tube you need to fill (spirals and any other imperfections will stand out). Also, as you are sanding your spot putty, if you over-sand the adjacent areas the gray primer will wear away and you will see it before you cut too deep.

Invest in some good sanding sponges-- 220 and 320 will give you a nice shiny smooth tube. They conform to the curve well, so don't leave flat spots or streaks.

When I want a first class result, this has worked well for me.

I've also heard folks first spray a white or black lacquer (again, fin areas masked off...). These dry hard and let you bear down more on the sandpaper as it takes more effort to cut through a lacquer that has hardened up. Another benefit is that a lacquer is non-porous and thus water won't easily soak through. If you are damp-sanding a primer coat later, water will go right through the primer and soften the paper tube, but would be stopped by a layer of lacquer. Haven't tried this but plan to sometime soon.

Marc

Good advice Marc. When I wet sand I always spray one coat of Duplicolor HBP (red) then after it dries I follow with Duplicolor HBP (gray) as I wet sand if I hit any red areas I know how deep I am let up. Wet sanding takes patience and a lot of practice...yes you can mess up tubes very easily if you get them too wet and sand through. After I wet sand an area I always wipe it down immediately!

 

[sodmeister]

Here`s what you want to look for Dan.

Don`t buy the UV activated stuff...pure poopoo !

Well look at that ,two picures of the same product ,must be your lucky day LOL

Paul T

 

[hornet driver]

Sod hit it on the head. I use the stuff on every build. If you use it over wood I suggest you prime first to get a good bond. I also use it for none structual fillets--or to glaze over existing fillets to smooth them out --sands easier than epoxy---as Sod said --it does shrink a little and is best put on in thin coats since it dries from the outside in--H

 

[kenstarr]

I'm a big fan of the glazing and spot putty stuff. I use it on balsa, paper, fiberglass, you name it! There are compounds that are probably better, but for me, this stuff rocks.
-Ken

 

[luke strawwalker]

I'm in agreement with all of Paul's notes but let me add one more:

I find that pre-spraying the body tube with a lightish coat of filler primer really helps me with this kind of spiral-filling job. I mask off where the glue joints will be for the fins, then spray the tube with Rustoleum auto filler primer (gray stuff). After that dries you will know EXACTLY where on the tube you need to fill (spirals and any other imperfections will stand out). Also, as you are sanding your spot putty, if you over-sand the adjacent areas the gray primer will wear away and you will see it before you cut too deep.

Invest in some good sanding sponges-- 220 and 320 will give you a nice shiny smooth tube. They conform to the curve well, so don't leave flat spots or streaks.

When I want a first class result, this has worked well for me.

I've also heard folks first spray a white or black lacquer (again, fin areas masked off...). These dry hard and let you bear down more on the sandpaper as it takes more effort to cut through a lacquer that has hardened up. Another benefit is that a lacquer is non-porous and thus water won't easily soak through. If you are damp-sanding a primer coat later, water will go right through the primer and soften the paper tube, but would be stopped by a layer of lacquer. Haven't tried this but plan to sometime soon.

Marc

"Water will go straight through and soften a paper tube"... I've NEVER seen or had that happen, PERIOD! If the tube is glassine coated (which is basically ALL rocketry tubes) then it's a non-issue. I damp sand EVERYTHING (including papered balsa fins) and have had ZERO problems with moisture from the sandpaper screwing up the works.

Also, "a lacquer coat lets you put more pressure on the sandpaper"... You don't want to use pressure on the sandpaper... that just gets things HOT and hot primer softens up, gets gummy, and clogs/ruins the sandpaper... GO EASY and let the sandpaper do the work... sanding lightly takes less work and does A MUCH BETTER JOB. Pushing down on the sandpaper merely creates deep sanding scratches in the surface that then must be sanded out with more sanding with finer grits, compounding the problem, as well as wasting energy (making the tube/sandpaper/primer hot) and the other problems I mentioned.

The sanding sponges are a good idea when one is starting out. Better yet is learning proper sanding techniques, which goes a LONG way in helping you do the best job with the least effort. I've tried every grit of sandpaper out there, and I've found that for general finishing purposes, I only need 2 grits-- 220 and 400 wet/dry. I keep a few rougher grits on hand for CONSTRUCTION sanding (shaping parts) and some finer stuff for detail sanding and really smoothing stuff out/delicate sanding work, but I don't normally use them in finishing. I've found that with 220 grit and 400 grit I can do everything from sanding down carpenters wood filler and bondo spot putty, sanding fillets and such, and sanding the primer in preparation for the final paint job. Once primered and dry, I sand the rocket with 220 grit, clean it up, then sand again with 440 grit to make everything REALLY smooth. The 220 grit takes most of the material off and "floats" everything out flat, and then the 400 grit finishes the surface and removes any sanding scratches or blemishes... damp sanding with 400 grit dipped in water and shaken off will take primer down to the point that it literally shines, which makes it easy to do a visual inspection of the surface, looking at reflected light off the surface of the tube to find any blemishes or low or high spots that cannot be felt or seen at right angles to the surface (hold the rocket up in line with a bright light source such as a window or lamp or overhead light, and observe the "glint" of light off the tube for irregularities, broken pattern, etc, and sand as needed).

The real trick to sanding is twofold. First, starting out, yeah, I recommend a sanding sponge or sanding block-- but once you get the hang of using it, you'll get better results with freehand sanding. The trick is twofold-- 1) move the sandpaper in small circular motions as you sand-- DO NOT sand in a straight line-- even up against fins, sand in small circular motions that just gently bump up against the fin or launch lug. Sanding in straight lines causes sanding scratches and grooves to be cut into the surface or flat spots... because more material is removed from that particular spot where the straightline sanding took place. So ALWAYS use small circular motions of your sandpaper..

2) keep the rocket moving CONSTANTLY as you sand-- DO NOT sand in one place-- this creates flat spots in the primer... I hold the rocket in one hand, and using 2 fingers with a small rectangle of sandpaper cut from the sheet with scissors (usually about 3 x 4 inches) over them, I sand in small circles while gently turning the rocket in my other hand very slowly... this will eliminate both sanding scratches (if you don't press down too hard-- that's why I only use two fingers-- to minimize pressure on the paper) and flat spots (if you keep rotating the rocket or part.

Good luck! OL JR

 

[luke strawwalker]

Paul

You can use it right from the tube without mixing or cutting it with anything. It's already the consistency?? Doesn't Wally World sell it?? I like to try it sometime and see how it works.

I don't dilute it with anything... IMHO it comes out of the tube at the ideal consistency... (but beware, the product can 'separate' like spray paint settles out in the can, only you don't have a mixing ball to 'shake it back to suspension again', so I'd advise storing the tube CAP DOWN-- this will cause the thicker pigments to settle down to the cap end of the tube, and the lighter solvents to work their way up to the opposite end of the tube... making it easier to knead the tube and remix everything before use-- if you store it cap UP, when you open the tube and go to squeeze a bit of the paste out to work with, sometimes you'll get a big squirt of bloody-looking fluid lacquer thinner with a little of the pigment left in it... which can ruin clothes and surfaces and stuff... plus it makes your tube of material get thicker and thicker over time... Storing cap DOWN prevents this problem...)

I've HEARD of people thinning the stuff down with various things (lacquer thinner being chief among them) to brush the stuff onto the surface, but I've never tried it like that... if i want a brushable filler, I mix carpenter's wood filler with a little water and work it in with a brush until it's the consistency of hot dog mustard, which works beautifully and sands quite easily.

Later! OL JR

 

[o1d_dude]

This thread reminded me that my tube of glazing putty had separated and I needed a new one.

Unfortunately, WallyWhirled was out.

 

[luke strawwalker]

This thread reminded me that my tube of glazing putty had separated and I needed a new one.

Unfortunately, WallyWhirled was out.

Metal tube or plastic?? If it's the plastic tube, it can be "kneaded" repeatedly for a few minutes until it "recombines"... the metal tubes are a LOT harder to do this with...

The stuff is still good, you just need to maybe squeeze it all out into a baby food jar or something like that and work it up with a stiff-bristled paint brush to recombine it... same way I work water in to carpenter's wood filler to get the hot dog mustard consistency that works so well for brushing on fins and nose cones. You can add in a little bitty dab of lacquer thinner if the stuff has gotten too thick from loss of solvent...

Or you can just buy another tube... but the stuff DOES tend to separate anyway because of gravity... LOL

Later! OL JR

PS. I hate wasting stuff... just threw out some stale corn chips and was debating if I had a recipe to use them in so I didn't have to waste them... haha.. worried about wasting a third of a bag of old corn chips... Guess I take after my Grandmother... (but I draw the line at reusing toilet paper like she did) LOL

 

[luke strawwalker]

Unfortunately, WallyWhirled was out.

BTW, I got some at Advance Auto Parts... They had two sizes of tubes... one of the tiny little plastic tubes maybe half again the size of a threadlocker tube, and a GIGANTIC steel tube about 8 inches long and about 3 inches in diameter like a mammoth toothpaste tube... the tiny little tube was $3 and some change. The gigantic tube was just over $4 bucks... Went on and got the jumbo tube, which is enough for a decade's worth of model building... LOL

Just store it cap down though! Later! OL JR

 

[o1d_dude]

Old school metal tube, Luke. For $3.48 at WM, it's easier to just pick up a new one when they're in stock.

Good suggestion about squeezing a bunch out and remixing...which is what I did at the time.

I've had the same issues with Squadron green and white putty.

 

[AfterBurners]

I went to Walmart and they were out so I just bought some the local auto part store. It was $5

 

[o1d_dude]

I went to Walmart and they were out so I just bought some the local auto part store. It was $5

Good to know. Thanks, Dan.

I'm on a mission today.

 

[dave carver]

The reason it goes on so well over primer is because that's what it is. Primer. Primer that's been thickened to a putty consistancy. No, it is not ment to go over raw, unpainted things. No, not for filling gaps. Spot putty for tiny holes in a primer paint job. I painted a drum set once. All the drums except 1 painted up nice. The one was from mahogany ply, ok if covered with a plastic cover but not good for a painted drum. The grain has small cracks that paint just doesn't fill. I spot puttied the entire drum, covering up all the cracks. Sanded it smooth and painted it over, hiding the cracks.

 

[luke strawwalker]

Old school metal tube, Luke. For $3.48 at WM, it's easier to just pick up a new one when they're in stock.

Good suggestion about squeezing a bunch out and remixing...which is what I did at the time.

I've had the same issues with Squadron green and white putty.

There ya go... I guess folks have a point when they tell me I'm so tight I squeak when I walk... LOL

Yeah, I guess any putties consisting of high solids with just enough thinner to act as a carrier and make it a paste is prone to that sort of thing...

At least it's not as bad as the yellow SNOT that squirted all over my hands the last time I tried to use my tube of plumber's putty... LOL

Later! OL JR

 

[Marc_G]

Interesting discussion here!

From my experience with slightly thinned spot putty, it does a very nice job in those cases where you want something with a bit more build to it than the typical filler primer. I sometimes dilute it just enough to make it brushable. Then I brush a coat of it on the surface, which as mentioned by others above is usually already primed or sealed. The thinned putty tends to dry with less shrinkage/cracking effects than the unthinned putty. Keep in mind, when working on a warm day, the unthinned stuff from the tube dries out so quickly that spreading it on a surface can be challenging. In the winter, not so much, and using a credit card type spreader as squeegee works much better than in summer when it's hot out. But it is definitely not a major gap filler or anything like that... it'll cover grain but not major cracks.

Also, an example of the dampness getting through filler primer happened last week when working on my Adfecta. I had sanded off much of the filler primer not in spirals, and in doing so had scratched the glassine. The damp (not wet, just a little damp!) sandpaper/sponge imparted enough moisture to the tube that it swelled a bit in spots. Some of these went through existing filler primer to the surface below (which had been previously smoothed lightly, scuffing the glassine). Glassine is just cellulose, after all, not plastic, so it presents no moisture barrier, particularly if it is roughed up increasing its surface area. In the end, it wasn't a big deal. The acrylic sealer I put on did swell the areas again a bit, but they shrank back as it dried. By the time I got to the top coat (again, using acrylics) all was well.

Marc

 

[o1d_dude]

I made a trip to Wally Whirled today on another matter and decided to check the automotive department hoping for a restock. And there it was. Paid my $3.48 for the new tube and left a happy rocketeer.

When I got home, I tried manipulating the old tube and succeeded in weakening the tube to the point that the orange oozed out all over my fingers. Oh, well. Pitched it and put the new tube in storage upside down.

 

[AfterBurners]

Well I had my fill of it today. Yeah it doesn't fill in gaps, which I found out and I didn't know to thin it on warm days like today. I basically wanted to blend my fillets, but after reading this thread it looks like this won't do it. I applied it to the fillets area with my finger..of course I used a glove. I applied just enough to cover the areas I wanted and used the same technique you would use thinning out epoxy fillets with rubbing alcohol. It dries up really fast. It looks like someone put peanut butter on my fillets so I have a lot of sanding to do tomorrow. Once I get all the fillets sanded down I'll spray it with primer and be done. I'm not going to concern myself with perfection on this project.

Check out the pictures on my G-FORCE build.

https://www.rocketryforum.com/showthread.php?47958-G-FORCE-Build/page6

 

[luke strawwalker]

Well I had my fill of it today. Yeah it doesn't fill in gaps, which I found out and I didn't know to thin it on warm days like today. I basically wanted to blend my fillets, but after reading this thread it looks like this won't do it. I applied it to the fillets area with my finger..of course I used a glove. I applied just enough to cover the areas I wanted and used the same technique you would use thinning out epoxy fillets with rubbing alcohol. It dries up really fast. It looks like someone put peanut butter on my fillets so I have a lot of sanding to do tomorrow. Once I get all the fillets sanded down I'll spray it with primer and be done. I'm not going to concern myself with perfection on this project.

Check out the pictures on my G-FORCE build.

https://www.rocketryforum.com/showthread.php?47958-G-FORCE-Build/page6

Best thing I've found for smoothing fillets is the Titebond Moulding and Trim Glue (TMTG). Water based, easy to work with, stays put, doesn't shrink, fills gaps, no runs, no sags, no drips, can be smoothed with a bare damp finger to a perfect finish (no sanding required), provides additional structural strength, no bubbles or voids to refill like yellow or white glue (unless you put on a fillet that is VERY VERY thick in one pass), dries clear, and primer/paint goes over it just fine. Can't ask for any better than that IMHO.

Right tool for the right job and all that ya know... Bondo Glazing and Spot Putty (BGSP) is good for some things, mostly for filling in surface irregularities... I prefer it over anything else I've tried for filling spirals-- (Carpenter's Wood Filler (CWF) just seems to disappear from the spiral as you sand it smooth, and I don't like having to do the same step 2-3 times to get the desired result-- BGSP does the job in ONE STEP). You're right that the stuff "sets up" VERY quickly when you use your finger, because the warmth of your hands evaporates off the small amount of lacquer solvent making it a paste. (You don't HAVE to use gloves, but you can if you want to). That's where a little "spatula" from an old Walmart gas card or something really helps, because it isolates the putty from the warmth of your hands while you apply it... I just daub it down into the spiral straight from the tube. IMHO thinning it or otherwise messing with it just causes more problems than it solves, unless you're trying to cover large flat surface areas with it (like apply it to fins to fill/seal them, which it's not REALLY meant to do-- might work, might not, depending on your technique.) That's pretty much all I use BGSP for is filling spirals and minor dings and such.

Later! OL JR

 

[AfterBurners]

Hey JR

I always value your advice and opinions. I agree with you on the (TMTG), but fins on my rocket is plastic AT G-Froce, so that's why I wanted to try the (BGSP) I posted my current pictures on my build thread and after they dried over night with the (BGSP) I sanded them down with 200 and then followed with 400. Shot a couple more coats of primer..looks decent. Things like this just take time and sometimes you have to repeat the process a few times to get the desired results.

Everything you stated is spot on.

 

[4kids49]

Has anyone used Aeropoxy Light Filler for filling in spirals or spot putty? How does it compare to Bondo and Elmer's Wood Filler?

Chris

 

[luke strawwalker]

Hey JR

I always value your advice and opinions. I agree with you on the (TMTG), but fins on my rocket is plastic AT G-Froce, so that's why I wanted to try the (BGSP) I posted my current pictures on my build thread and after they dried over night with the (BGSP) I sanded them down with 200 and then followed with 400. Shot a couple more coats of primer..looks decent. Things like this just take time and sometimes you have to repeat the process a few times to get the desired results.

Everything you stated is spot on.

Yep... didn't know what you were working on til I noticed and followed the link later on. My bad... LOL

If the gap is small, the BSGP might be the ticket... if it's bigger, probably better to just fill it with another dab of epoxy... Have you tried epoxy and microballoons?? I hear that's the real ticket to doing fins on composites... sands easy and it's lighter, while still having the "bond darn near anything" and strength of epoxy...

Later! OL JR

 

[luke strawwalker]

Has anyone used Aeropoxy Light Filler for filling in spirals or spot putty? How does it compare to Bondo and Elmer's Wood Filler?

Chris

I haven't used that particular material, but I have used some ultra-lightweight spackle... the kind with microballoons in it and the container feels empty when you buy it at the hardware store... stuff looks and feels like Cool-Whip with granulated sugar stirred in... LOL

I didn't much care for it. It's a little more substantive than Carpenter's Wood Filler (CWF, the Elmer's stuff) but in sanding it, I'd still have to make a second pass to really get rid of the spirals... I wet a brush and daubed at the spackle ("cake frosting") and brushed it onto nosecones and transitions I had hardened with CA for a build, and then sanded it down. Didn't appear to fill as well as the CWF, IMHO. SO, I've switched back to the CWF for filling balsa nose cones and transitions... and I prefer the BGSP (Bondo Glazing/Spot Putty) for filling spirals...

Those materials just seem to work the best for me in those roles... with the least hassle and repetitive effort required...

Later and good luck! OL JR