Chris, thanks for those.... And, yep, those are the ones the art guys are starting to use for sure.....

interesting!
Jay D.

Thanks for the feedback, guys. I was pulled away unexpectedly so couldn't reply to this until now.

I think the problem lies in my primer blocking. For that particular panel, I primed and blocked it three times but still had some high spots showing through (it was aluminum so they were sanded pretty flat - couldn't see them). I used guide coat with 180 / 320 / 600 grit. The panel looked and felt super straight.

I'm checking out those Youtube videos and I think that maybe a longer, somewhat flexible block could be what I need (I'm using an 11" Durablock now).

BTW, those Youtube videos seem to describe the problem perfectly. I used firm 11" Durablocks and noticed while spraying my second and third layers of high fill primer that my low spots seemed to be moving around. I wasn't sure if it was my imagination or not but I've ordered one of the flexible 24" acrylic blocks mentioned above and will report back.

Those acrylic blocks look very interesting but they are not cheap by any means.
https://linearblockingtools.com/ols/cat ... created_at

Is there another source for them?

Definitely not cheap. My take after watching the videos is that he invented them, so he's likely the only source.

I will most likely sell the one I just purchased (24" flex) when I'm done with it. I only need it for six more panels and I'd rather not keep it in my garage forever.

just an idea and most of you probably already use them. but foam pipe insulation works good for non flat areas. its available in many different sizes. i'm old school so i use a rolled up magazine.
Jay D.

FWIW I purchased the 24" flex acrylic sanding block mentioned earlier in this thread. Pretty nice quality. I've been using it on my fenders which have a lot of typical 50s era curves. They do a nice job smoothing things out so far. The only complaint I have is that they have little give so they tend to go right through the epoxy on the crowns.

ot1138 wrote:The only complaint I have is that they have little give so they tend to go right through the epoxy on the crowns.

From what I've seen they have 3 different grades of flex, so it sounds like the one you have is too stiff.

ot1138 wrote: The only complaint I have is that they have little give so they tend to go right through the epoxy on the crowns.

Depending on how you are sanding those crowns, it may have more to do with your technique than the block.