When to add filler?

[blacktop]

Need help on the best way to go about when to do the filler work. I have the 1/4s stripped I DA them with 80 also the roof once I had them sanded I put ospho on them and was planning on putting the car in DP. Now I'm thinking if I should just to the mud work on the bare metal then Dp. I can't work on it all the time so next is to strip doors and fenders. This is a 46000 mile clean Chevelle. Thanks for any suggestion...

[mitch_04]

I use a lot of SPI products and they recommend filler on top of epoxy for best adhesion.

[Musclerodz]

Do not mud on top of ospho. The phosphoric acid in it can react with the filler. You need to epoxy it first.

[Musclerodz]

I use a lot of SPI products and they recommend filler on top of epoxy for best adhesion.

You are not suppose to treat the metal before using SPI products, per the instructions and a you tube video test I have seen with SPI products, it can inhibit adhesion when using acid etches before SPI

[blacktop]

Ok thx. I'm using DP 90 it might sit awhile till I can get to the body work so should I scuff it with 80-180 before wiping mud?

[dhutton]

Ok thx. I'm using DP 90 it might sit awhile till I can get to the body work so should I scuff it with 80-180 before wiping mud?

Yes.

[mitch_04]

True, but Barry has stated that when you have situations where it is necessary (someone with pitted metal and no sandblaster perhaps?) Ospho is the only treatment he recommends. He states that whoever is using the Ospho treatment should call SPI and make sure to neutralize it a certain way, which is basically making sure to rinse it while it is still wet. If the Ospho dries, you need to reactivate it and then rinse it. Question comes up often on the SPI forum.

You are not suppose to treat the metal before using SPI products, per the instructions and a you tube video test I have seen with SPI products, it can inhibit adhesion when using acid etches before SPI

[mitch_04]

A quote from Barry on a thread discussing the video I'm assuming you were talking about

"You are right, I get the horror stories on the tech line after the job is done.
SPI ONLY recommends three kinds.

PPG, Dupont or the Ospho because we know what we are dealing with and all three have been out for many years and not changed with every batch made."

Link to thread...
http://www.spiuserforum.com/forum/spi-company-products-updates/70776-spi-epoxy-torture-test/page4

[Musclerodz]

A quote from Barry on a thread discussing the video I'm assuming you were talking about

"You are right, I get the horror stories on the tech line after the job is done.
SPI ONLY recommends three kinds.

PPG, Dupont or the Ospho because we know what we are dealing with and all three have been out for many years and not changed with every batch made."

Link to thread...
http://www.spiuserforum.com/forum/spi-company-products-updates/70776-spi-epoxy-torture-test/page4

good to know, always exceptions to the rule that is why questions need asked and instructions followed.