Second coat of Bilt Hamber epoxy mastic

[ashy90]

Due to weather and lack of time, it has been a week since I applied the first coat of Bilt Hamber Epoxy Mastic grey to the underside and wheel wells of my car. I know other epoxy mastics such as Jotamastic have a time period for recoats without the need for sanding etc, so I'm assuming it's the same with the BH product, and I should be prepping the surface now before applying a second coat?

 

[steveo3002]

whats the tech sheet say? they respond to questions if you email them

 

[ashy90]

whats the tech sheet say? they respond to questions if you email them

Very little - just says hard dry in 7 hours. Slower if below 10 degrees.
No information on second coats

 

[qwakers]

a week is well into the time period you need to re prep for a second coat. Buy some coarse scotchbrite and go at it.

 

[ajlelectronics]

Due to weather and lack of time, it has been a week since I applied the first coat of Bilt Hamber Epoxy Mastic grey to the underside and wheel wells of my car. I know other epoxy mastics such as Jotamastic have a time period for recoats without the need for sanding etc, so I'm assuming it's the same with the BH product, and I should be prepping the surface now before applying a second coat?

Going by the Lechler TDS, 120 grit is for initial primer coats. For sealer (subsequent) coats, 320 is specified. Bilt Hamber must have a TDS.

 

[atomant48]

Very little - just says hard dry in 7 hours. Slower if below 10 degrees.
No information on second coats

In my experience with that stuff (brilliant that it is) 7 hrs is a stretch. Could be my mixing or the temp I guess.

 

[badabec]

No TDS that I can find, a sparse data sheet is the only thing I can find from their website.

 

[Zedd]

If it's been a week, you should give it a light key with some sanding or a scuff pad. Bilt Hamber recommends recoating within 24–48h for chemical bonding. After that, it's mechanical adhesion only.

 

[ashy90]

Thanks guys.
Have sanded/keyed it, and now applied a second coat.

How long should I wait before applying a top coat / stone chip?
If I applied it in approx 24 hours time, would I need to key the surface again first?

Seems a good product to use but no technical data sheet and limited instructions.

 

[Smallfry]

Thanks guys.
Have sanded/keyed it, and now applied a second coat.

How long should I wait before applying a top coat / stone chip?
If I applied it in approx 24 hours time, would I need to key the surface again first?

Seems a good product to use but no technical data sheet and limited instructions.

Best to ring or email Peter at BH. I am sure I have seen a TDS for their Epoxymastic.

 

[charlysays]

I'd second giving BH a ring if the TDS is a bit vague as they sometimes can be. A lot of epoxy mastics have an enormous re-coat window (with itself). For example, jotamastic 90 winter grade can be re-coated with itself any time within 3 months which makes it really handy for restoring the underside of your car in sections.