Trouble with spraying epoxy

[Dcal]

The selemix can be thinned to suit a standard spray gun but when you do, it is "very" easy to get it to run.
Once you realise that it's nice enough.
Jotamastic 90 on the other hand is almost impossible to get to run no matter how much thinner you add, however it's not recommended for a conventional gun (but that hasn't stopped me from using one)
If you overthin you can get a nice finish but at this level of thinning you are outside Jotan's recommendations so I wouldn't use it that way for anything mission critical.

I use the Selemix for it's wet on wet capability which can certainly speed up the process.

 

[norsa]

I agree with you on the run ability, you almost need to put a dust coat on followed by two wet coats but it goes on nicely and I use it a lot for suspension and engine parts as a satin finish coat. It flats nicely and as said, has a good window for wet on wet.
Nick

 

[Munkul]

Sherwin williams

Which one though?
All the big industrial paint makers do loads of different ones. Case in point, the two different hempadur products. Same name, different number, and completely different applications.

 

[Turbo]

I have used the selemix through a touchup gun with a small tip (0.9 I think). To do that I had to thin it down a lot. It is prone to running or sagging so you need to apply it in thin coats.

 

[jo1010]

I don't get why there are so many problems - maybe the industrial stuff is very very hi build, but on car panels I've used hb body (cheap) and lechler ( not so cheap and better finish) with no unusual problems......always using the same product hardener AND appropriate thinner added to suit conditions and 1.8 tip hvlp (2 coats).... I think Lechler spec an epofan thinner, but hb body wasn't fussy. The bigger the job, do more test sprays....

 

[Munkul]

I don't get why there are so many problems - maybe the industrial stuff is very very hi build, but on car panels I've used hb body (cheap) and lechler ( not so cheap and better finish) with no unusual problems......always using the same product hardener AND appropriate thinner added to suit conditions and 1.8 tip hvlp (2 coats).... I think Lechler spec an epofan thinner, but hb body wasn't fussy. The bigger the job, do more test sprays....

I think my main problem was starting with the wrong product altogether. It's a very high build, high film thickness industrial coating which needs 250bar airless spray to work well.
That, and complete ignorance of what epoxy paints are "supposed" to be like. Honestly, I just didn't appreciate what a massive world of difference there was between products.
Hempadur 45143 has a reccomended dry film thickness of 150 microns, as opposed to Selemix 7-413 which is 40-80 microns. That's a huge difference.

 

[jo1010]

....Hempadur 45143 has a reccomended dry film thickness of 150 microns, as opposed to Selemix 7-413 which is 40-80 microns. That's a huge difference.

I wouldn't get too hung up on the figures for airless .....and I'm not even sure the dry film thicknesses are spec'd in the same way between manufacturers. I looked at the Lechler specs for a comparison.....So for a heavy duty Lechler epoxy primer they too quote airless between 80 and 150 bar while quoting the usual 2 to 2.5 bar for hvlp with 1.8 to 2.0 tip... On that product around 200 microns wet film and needing 2x coats to achieve 200 micron dry film. That's for their S2402 epoxy but I've only used S107 which has a much lesser specced 70-100 micron which flows nicely so it could well be the heavier product is more sensitive to set up......also bear in mind 20 degrees C reduces recoat time to 1hr - which increases a lot with colder temps (10C sounds too cold to me)....I'd also be warming the paint pot with that thick stuff irrespective of outide temperature.....

 

[norsa]

Im lucky to have a pro set up to spray in and dont really pay a great deal of attention to build and ratios, i use a product recommended by my local paint supplier and make it work for my requirements. Consistency and gun set up is the key.
Nick