High Build Primer?

Hi all- I'm attempting my first fiberglassing job, and I've gotten inconsistent coverage- some areas are epoxy-rich, and need to be sanded back, and other areas have the weave of the cloth visible, but are clearly saturated. As I understand things, the latter is the better of the two scenarios- maximum strength (remember, no dry fibers) with minimum weight. Trouble is, I want the finish to be mirror smooth.
What high build primers do you use? I was googling around and found some excellent reviews of a rattle-can 2-part epoxy primer from Eastwood, but it's pricey at $22 per can for the high-rated grey (look for Eastwood 2K Aerospray on Google if my link doesn't work)
Has anyone used this? It seems all the rage in the autobody world, but if I can find something in the $8-10 range, I'd be more comfortable. I have to keep reminding myself this is just a hobby, not a living.

Thanks!

Rustoleum 2X high build is a preferred primer for about 5$ for 1 can,

conman13 said:

Rustoleum 2X high build is a preferred primer for about 5$ for 1 can,

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That's more like it, thanks! PS- born and raised in Scotia, 'bout 30 minutes from Delmar...small world! Hope spring is kind to you, winter sure wasn't!

conman13 said:

Rustoleum 2X high build is a preferred primer for about 5$ for 1 can,

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+1.

conman13 said:

Rustoleum 2X high build is a preferred primer for about 5$ for 1 can,

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+2.

soopirV said:

That's more like it, thanks! PS- born and raised in Scotia, 'bout 30 minutes from Delmar...small world! Hope spring is kind to you, winter sure wasn't!

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It's a small world after all....


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So, follow up question- do you guys ever have problems with top coat compatibility? I am not a fan of rustoleum paint, I feel it's too brittle, so I tend to use Krylon or Ace brand. Any one try either of these on top of the Rustoleum high build?

No problems with either--I've used both over it.

conman13 said:

Rustoleum 2X high build is a preferred primer for about 5$ for 1 can,

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Ditto #3

I use Finish1 (Martin-Senour) and get it at NAPA. It runs about $30 a quart and you do need to be able to spray it. It reduces with acetone and is self catalyzing. Dries in about 30 minutes and is block sand-able in about an hour. I use a $10 spray gun from Horror-freight and it woks very well. This stuff sands to a glass like finish and has worked with

• Two part urethane paint
• Water based acrylics
• Rattlecans by:
  • Krylon
  • Rustoleum
  • Duplicolor
  • Valspar
  • And a couple of brand z entries

While $30 sounds like a lot it is the fluid equivalent of 12 rattle cans. My ciphering says its a good deal.

Primer is an expensive way to fill a surface. Most of your hard earned money ends up as a pile of dust on your floor.

The best product I have found for smoothing a surface is "USG Icing" available at your local auto refinishing shop. Its like bondo but without all the fillers. It can be brushed or squeegeed (my preference) on. It's not exactly cheap but a little goes a long way.

https://www.sgcardetail.com/USC-26006-Icing-Pourable-Polyester-Finish-Putty-24oz-Prodview.html

I have used the rustoleum high build primer from the auto section in walmart. .cheap and easy to restock.

On bigger projects have bought the lacquer primer from the body shop supplies and shot with cheap harbor freight gun

Kenny

Ya know, it sounds like all of us in our enthusiasm to answer your question , may have steered you in the wrong direction. Your wasting your time trying to fill FG voids and dimples with high build primer---your process is wrong-----Follow this and you won't go wrong--THERE IS NO SHORT CUT --if you want it right !!!---Let's start with sample A-- Sample A is your whatever that your made and has some varying degree of resin over it's surface----Those nice glossy , slick spots---those are high and you need to knock them down just a tick---Block sand the entire surface with some 220 grit. Wrap some sandpaper tightly around a wooded paint stick and work the whole surface. You don't need to make them disappear--just knock down the high spots--you'll know what I'm talking abpout when you start. If you dig into the fibres , you've gone too far !! Next--apply spot putty---just really thick primer in a tube--- over the entire surface with a blade of some sort--plastic works best. Let it dry and knock it down with blocked 220. HeY, get back over here !!!!! Now, do it again !! I'm assuming your surface was really bad to begin with . NOW it's time to prime. Lay on some good coats of primer. Let is dry for a couple days--it continues to shrink as it cures. WAS THAT SANDABLE PRIMER YOU USED? If not your gonna need to moist sand it with 400. You need to continue to block sand with lighter grades of paper but I usually just jump to 400. Now spray a guide coat---A different color and it does not have to be primer----- over the subject---basically just dapple it from a distance---you'll have little spray particals all over the subject. Now sand the whole surface again lightly until they are gone ----this helps you find all the low spots you can't find but will show up in your nice gloss paint ---and you should have a perfect surface- a flexable sanding sponge is really good for this--you can get them at most art stores ----Now that your Head is about to explode---just go over to my 20 MILLION MILES to EARTH build sight and you'll see what I'm talking about along with all the possible mistakes along the way. To bottom line it---there's no short cuts--The better you want it to look the longer ya gotta take and the more steps are needed....H

Filling in pinholes, etc., is a pain in the butt. I get it. But jderimig and Hornet driver are right. Glazing putty is GREAT, but it's expensive. I've used Aeropoxy light filler with good results...


Later!

--Coop

hornet driver said:

Ya know, it sounds like all of us in our enthusiasm to answer your question , may have steered you in the wrong direction. Your wasting your time trying to fill FG voids and dimples with high build primer---your process is wrong-----Follow this and you won't go wrong-

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Thanks for the lesson! I didn't see it until after I spent the weekend working on it, but actually stumbled onto a process that is similar. Knocked off the high spots without cutting into the fabric, then instead of spot putty I made a batch of epoxy with Q-cells, and laid that down. Once cured and sanded, I filled the little spots with fill-n-finish. Think I'm almost there.

How does Rusto 2x compare to Duplicolor filler primer? I like the latter for fast-drying, but it's a tad pricey.

Zeroignite said:

How does Rusto 2x compare to Duplicolor filler primer? I like the latter for fast-drying, but it's a tad pricey.

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Your better bet is Rustoleum Automotive Filler-Primer. It is lacquer-based and thus is fast drying. I have found it to fill better than Duplicolor. You find it at Walmart in the automotive section for a little over $4 per can.