Brush vs Rattle Can

I chimed in on a thread, cannot remember where, about filling spirals on tubes. I made mention to the amount of paint lost to overspray when doing this and asked why we don't use a brush and high build primer to do the job. Well, there was no answer and a good luck and let us know if you try it. So I did (am).

First coat is on. I can tell you from an application standpoint I am using way less primer.

Here is what I am doing and what I am using. I will post photo's after I am done with the primer project. I am building a Madcow Frenzy in hope of gaining level II this summer. I fiberglassed the top 4" of each tube to strengthen them along with gaining a little experience in fiberglassing. The primer I chose is Dupli Color professional Primer Surfacer. Purchased a quart for 17 dollars. Supposed to be a high build primer. I applied it with a 1/2"ish brush. I applied the first coat rather thick is some spots and thinner in others to see what difference it will make. The primer has a very high VOC content and skins almost immediately. That is both good and bad. Dries fast but also dries in the cup used for application. Stirring frequently seems to help. Based on how it is drying I am guessing I will have to do 3 coats. Application took me about 10 minutes for this rocket. 4" diameter and 62" of tube spirals to fill.

It is drying now. Sanding a little tomorrow and another application. Will let you know how it goes.

I used a brush many years ago (~50) and it took forever to sand it smooth. Spray is worth the time saved, at least to me. However, I'm sure paint technology has changed a lot since then. Let us know how it turns out. I may go back to the brush.

This has gone much better than I expected. I believe the one coat did it. After drying I hit the entire thing with one of my Hitachi palm sanders (220 wet/dry). It made quick but dusty work of the primer and brought the entire thing down to a smooth surface. Thank goodness for dust collectors. I think one more coat by the fiberglassed section to fill the transition and then a final full coat over then entire tube will do it. Palm sander between coats then maybe a little touch up by hand and done. Overall I think I have a half hour invested in it and maybe a dollars worth of primer. I would recommend this to anyone trying to fill spirals. By the way this dries and is able to be handled much faster than the rattle cans I have tried.

I've been told I'm doing something wrong, but looks to me that spray paints don't fill spirals, it exaggerates them. I finally did my last with 89 cent art paint for primer, was going to try brush last time but rebelled at not being able to get a decent can of paint for less than $5.

I think I'll stick with Bondo(Spot and Glazing Putty) for filling Spirals.
I can't immagine ANYONE actually tries to fill them with Spray Can Paint/Primer.

Never filled spirals. Got a quart can of primer to try rolling on bigger rockets. As long as I sand it, I don't think it matters how I got there.

Most of my rocket arrive at a launch still carrying dirt from the previous launch, so I'm not too picky. Slowly improving my finishing effort.

Personally I use bondo glazing and spot putty... Basically its the solids from primer with just enough solvent (lacquer thinner) to make it a paste... I rub it into the spirals and it dries in a matter of minutes, and sands easily, and smoothly, rarely needing and secondary work, ready for priming...

Later! OL JR

luke strawwalker said:

Personally I use bondo glazing and spot putty... Basically its the solids from primer with just enough solvent (lacquer thinner) to make it a paste... I rub it into the spirals and it dries in a matter of minutes, and sands easily, and smoothly, rarely needing and secondary work, ready for priming...

Later! OL JR

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I heard of this, didn't seem to be any of the bondo types at home depot. Just regular bondo and fiberglass resin.

Just googled it. Wasn't looking for a little tube. LOL.

cavecentral said:

I heard of this, didn't seem to be any of the bondo types at home depot. Just regular bondo and fiberglass resin.

Just googled it. Wasn't looking for a little tube. LOL.

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Check Walmart, Meijer, or your local NAPA auto / Advance Auto or whatever your local chain is. Look for this:

https://www.shopdirectbrands.com/3m-bon-gsp.aspx

In stores it usually goes for around 5 bucks a tube.

Marc

Have to say either method will work just fine. It's all in what the individual is comfortable using. For years I used brush on fillers but when I discovered K-Mart Cheapy 88cent Primer I found I perfer using the cheapy spray primers over any of the many brush on stuff I've tried as the rattle-can primers IMHO are fast, easy and create a better end finish then brush on stuff. Lately I've switched to Wal-Mart Cheapy auto primer a bit cheaper and easier to get in case lots.

I call the application method three's; apply 3 heavy coats and allow to dry. sand with 240grit. generally that's all that's needed. Occasionally on really bad tube seams or very deep balsa gain a second 3 coat may be need but usually the first three is all that's needed. Once you're happy with the primer finish a light 360grit sanding is all that's needed before the base color coat.

It just depends on which method make YOU happy

Not familiar with grits smaller than 180. LOL.

cavecentral said:

I heard of this, didn't seem to be any of the bondo types at home depot. Just regular bondo and fiberglass resin.

Just googled it. Wasn't looking for a little tube. LOL.

Click to expand...

Yeah...its an auto supply thing... Car bodywork...

Be careful, tho... I found I could buy a little bitty tube for like $3.99 or a gigantic tube for like $4.99...

Also, using lacquer thinner, don't apply it over enamel primers if you don't want them crinkled.....

Later and good luck! OL J R

I have used Bondo but found it very tedious so it drove me to find a different solution. I still had to sand and the application seemed to take forever. On top of that I still have to add primer. The rattle can method works for me but like I said in my original post, half of my paint or primer goes on the floor. Not something I enjoy seeing or having to clean up. The primer I am using for this experiment has a very high solids content which means it can fill fairly large gaps, dents and spirals with one or two applications. The applications are specific to the problem area which means I am not sanding away a bunch of it resulting in even more waste.

I am not claiming this is the correct method. Just one I thought might work and seems to be working for me. If anyone is frustrated with their current method I encourage them to try this method and the primer I tried. Cannot say it would work the same with thinner primer. I have a full coat (haven't decided if that will be brushed or sprayed) left to apply then a sanding and on to painting. Paint will still be sprayed.