A recent post by Lee got me lamenting the loss of 3M Bondo gray Filler Primer, after which I had switched to DupliColor Filler-Primer FP101. Not totally happy with this, I picked up some Seymour PBE Filler Primer (20-1674), and it seemed better than FP101, so the Dupli-Color moved to the back of the shelf. While fixing my Mega Der Red Max (again!), I thought I'd try the 2 primers on opposite sides of a fin and do a side-by-side test.

The fin is nearly finished, and just needed another coat or 2 of primer, so I sprayed DupliColor FP101 on one side, and Seymour PBE on the other side. Both dry very fast, so put on 4 thin coats, about 2 minutes apart. Both cans have an fan style sprayer that can be rotated, and went on nicely. Both cans cleared quickly with a brief spray upside down.

After drying for about an hour (longer than needed), I cut 2 squares of 3M 320 grit, and 2 squares of Gator 400 grit. Both sides of the fin were sanded with their respective sheets, first 320, then 400.

For the 320 sanding, there wasn't a big difference. Both sanded nicely, and neither sandpaper clogged, a quick brush of my hand cleaned it off.

For the 400 sanding, the difference was significant. With the Seymour, I stopped sanding after it felt sufficiently smooth, though it was still sanding nicely. With the Dupli-Color, after a bit of sanding the primer developed a sheen that was no longer sandable. Both primers clogged the 400 moderately, as can be seen in the photos.

The photos of the fins post-400 sanding were taken with the fin angled for maximum light reflection from the window. The photos show 320 & 400 grit paper after use, Seymour on the left. Though the Seymour 400 appears more clogged, it was still sanding reasonably well.

Though I rarely use 500 grit, I tried a little sanding of each. The Dupli-Color side wouldn't sand well, it seemed like the surface was harder, and produced very little sanding dust. The Seymour side sanded fine. There was moderate clogging with both.

My preference after this brief test is the Seymour PBE. YMMV.

Attached Thumbnails

     

__________________
Paul
If we weren't all crazy, we would go insane - Jimmy Buffett
NAR #87246 www.wooshrocketry.org

There are several different varieties of Seymour PBE available.

SKUs I'm guessing you might have tried include:

20-1671 Seymour PBE Professional Primer Spray Paint, Sandable Gray (15 oz.)
https://www.seymourpaint.com/produc...ble-gray-15-oz/

and

20-1674 Seymour PBE Professional Primer Spray Paint, Gray Filler (15 oz.)
https://www.seymourpaint.com/produc...y-filler-15-oz/


Could you post a pic of the can or SKU?

Before adding the primer, what was used to fill the grain?

I've clarified the OP with the part number 20-1674, thanks for pointing that out.

__________________
Paul
If we weren't all crazy, we would go insane - Jimmy Buffett
NAR #87246 www.wooshrocketry.org

Nothing. These are huge fins, too much balsa to bother filling. Multiple coats of primer filler do a pretty good job, certainly good enough for where I fly.

__________________
Paul
If we weren't all crazy, we would go insane - Jimmy Buffett
NAR #87246 www.wooshrocketry.org

So where do you buy Seymour paints?
I went online to see if there are any retailers in Cedar Rapids but what I get are ads for every paint and hardware store in town without any definite hits of yes they actually carry it.

This is what the OP used:

https://www.amazon.com/gp/product/B0088LVJU8/

Thanks!
I now have one on order.

Paul,

Thanks for posting your experience using the Seymour primer. My order should arrive on Monday.

We have gone from high 90s to 50s and rain. May be a delay in trying it myself.

__________________
Lee Reep
NAR 55948

Projects: Semroc Saturn 1B
In the Paint Shop:
Launch-Ready:KFD Mini Satellite Interceptor

I've ordered a can of the Seymour as well. I will be interested to see how it does.

I used a different DupliColor filler primer (not FP-101) on my Viking for NARAM and it was a mixed success. I think the only reason I got third place in C Division is that there was so much carnage. But the Viking flew beautifully.

__________________
Bernard Cawley
NAR 89040 L1 - Life Member
SAM 0061
AMA 42160
KG7AIE