porchdog

dont know if i mentioned this or not. the guys using spi have discovered it works best to shoot a reduced coat as a sealer before color. you will get better adhesion this way. i sand down to 600 then seal before color.

929nitro

Thanks for the tip. Is there a set amount to reduce it by?

porchdog

just a little. maybe 10%. just enough to shoot it smooth. doing this will give you a better adhesion. most everything is cross link now days. just sanding does not ensure a bond. i seal over 320 or 400 then start base color.

929nitro

Pardon my ignorance, just trying to understand. First you mentioned sanding with 600 then sealing and then you mentioned 320 to 400. When would you use one rather than the other. Thanks for your time I enjoy doing but am not the most knowledgeable but am learning from guys like you and others here.

porchdog

if the epoxy has cured for a long time i hit it with 320 or 400 depending on how it looks. if the epoxy is a week to 10 days old i'll hit it with 600. i scuff the sealer with 600 if i have trash to get rid of.
older epoxy 320-400 for some teeth .
fresh epoxy 600 for trash before color.

71white

I want to thank you Porchdog from all us novice guys. Even the smallest tips are new and helpful to us.

car71

Its that wet sand or dry sand.

mayordaly

P-Dog, last time I used SPI epoxy I thought it went on, on the thick side. If I mix to spec. to the data sheet do you thin more with laguer thinner or What? Or just less epoxy base?
And thanks again for all your advice. You Da man!!!

maddoggyusa

Porchdog,

I contacted Barry at SPI about my '80. It is very clean and needs very little body work.

He told me on such cars he'll just use epoxy primer only for blocking... no urethane primer whatsover.

1) Do you agree this is a good idea?
2) What is a good process for the urethane bumpers? Can I use epoxy on the these as well?

Thanks!

929nitro

Thanks for the info. As always I look forward to you and others on this sight.

claysmoker

Hey Porch. Are you using the standard silicon carbide 3M wet or dry sandpaper for wet sanding?

Thanks a lot for helping us out here, very much appreciated. Wish I was closer to Texas, you'd likely be painting my '64.

Dave

porchdog

i wet sand everything except final clear . jim c on the spi site got me to doing it. works pretty well with the da.
when i first talked to barry i told him i had 0 use for urethane or polyester primer. i wanted an epoxy for surfacing. his did the trick. it reduces with urethane reducer. for build i shoot it 1:1 and use my iwata. shoot it slick and wet. after my final blocking i will reduce about 10% for a sealer coat. then start color. it works great on urethane bumpers with no flex added.
i just shoot one coat of epoxy really thick and wet. let cure for 24 hrs or so and block. when i'm happy with it i start painting. i parked the 57 in the sun a few days ago for an hr or so. very little ghosting so i'm happy.
clay , my next project is a 56 210 for a fellow in California . it's strange. most of my work shows up in a transport. somehow the last 3 have been within 110 miles. good luck with it.
damn forgot your question . i use 3m and mirca paper.