|Today 05:20 AM|
|Yesterday 09:45 AM|
The instructions for SPI epoxy are clear.
Sand metal with a D/A and 80 grit.
Where I can't get to with a D/A, I think the finish that a media blast leaves is good too. I use Black Diamond media.
|Yesterday 08:11 AM|
|Chevymon||Mike, you have given a lot of good information here, but I just don't agree with what you are saying, and I use SPI also. BTW, Its hard for us--at home--to match what the factory was doing with primer 60 years ago.|
|Yesterday 06:46 AM|
|Yesterday 06:24 AM|
|deadbodyman||When the factory sprays epoxy the metal is NOT sanded...I don't know about other epoxies ,I only use SPI ,its been so long now I don't remember using anything else since DP-40... IMO most epoxies are about useless PPG hasn't had a good epoxy primer since DP-40 even then,as good as it was, it sanded like a rock,the only way to sand it was with 80 grit...It's also a good idea to check your adheasion before starting your filler work .I do this with a razor scraper and try scraping the epoxy off the metal but in most cases the average guy can test adheasion by sanding the epoxy down to the metal with 180 and feathering the epoxy back to make sure it feathers back nicely with no broken edges....|
|04-25-2015 07:28 PM|
pugsy is totally right on that. I use a hand held brush, like a tooth brush but it needs to be stainless steel. It doesn't throw the acid all over the place, and you don't have to reapply as often. Just like he said, you have to keep after it until its just shiny white metal when reapplying. If you get a sludge, that has to all come off while the sludge is dissolved.
Mike, I'm sure you know, but for those that don't---- as far as I know all the epoxy manufacturers require an 80 grit DA scratch on bare metal, although PPG is OK with 180 scratch when using their metal prep with zinc phosphate in it.
Tamco paint makes an epoxy---similar to what boeing uses---that can go over anything, even if its unsanded, but they still recommend sanding when ever possible. And they claim to be the only one available to the public with that option. I have used it and it works.
|04-25-2015 05:06 PM|
I've used a rust convertor which is basically the same as Ospho. The instructions state that the black converted rust is ready for primer and paint but it's a bunch of bull.
I ended up using a small spot blaster to get into the pits.
A wire wheel in a grinder or drill may sometimes get it all out.
Apply more acid and if it turns black, you're not finished yet.
Eventually, the acid won't turn anything black anymore and you've got all the rust out.
|04-25-2015 11:28 AM|
DeadBodyman, My concern now if how I can get rid of the minor black freckles left on the paint. I was hoping that these spots, which were there before the ospho treatment, were already there. Theyre a PITA to take off and was hoping I didnt have to grind them off the entire car?
Any opinion on this? Im I over thinking this?
|04-24-2015 02:58 PM|
|deadbodyman||yes, sometimes I do ,sometimes just 80. I tend to work through the grits when prepping bare metal. once it starts shining and getting super clean I have a hard time stopping But I use epoxy for everything, over my filler work and as a sealer when I need one.its a self etching primer too, so it sticks great to unsanded metal as well .theres really no need for any other primers ,SPI epoxy is all I use 95% of the time|
|04-24-2015 11:03 AM|
|04-23-2015 05:23 AM|
Theres many ways to "remove" rust,Ospho is one of them without the mess of media blasting.
Ospho has some advantages over other methods like removing rust on a running and driving car because you don't have to worry about the glass and sand getting into the motor and other moving parts ,causing problems down the road.
If you use Ospho be sure to remove the protective coating that keeps the metal from rusting....
theres two ways to remove the coating when your ready to prime. 1) thuroly sand it off or 2) rewet with more ospho and rince off while its wet. I prefer sanding it off ,starting with 80 then 180 and finally 320 all dry sanded with a DA.. and a wire wheel on the pitted rust ,slowly with a coarse wheel as not to polish the surface.
So far SPI epoxy primer works best so its a great combo...
when done properly there are no adheasion problems BUT it does have to be done properly if not you WILL have problems so "yes" use it but use it properly. I've had great success with it for many years with no problems at all.....
|04-22-2015 02:32 PM|
|shine||i think you need to watch the beginning of the video again .|
|04-22-2015 02:19 PM|
Can someone briefly summarize this thread for me?
So should I use Ospho or not?
Im leaning to using it based on this.. Also using SPI Epoxy
|11-17-2014 06:48 PM|
You didn't get the boot yet.
They're back now.
|11-17-2014 11:12 AM|
|deadbodyman||I thought I got kicked off the site again...|
|This thread has more than 15 replies. Click here to review the whole thread.|