questions on poly primer. Temps, sealing

[dannyho]

I'm planning on painting the car soon. My plan is to get it bare metal, epoxy primer it, then after doing the more major work to be done, putting on the poly primer. I also had read that it was a good idea to spray epoxy over the poly again (I'm leaving out all the sanding steps in between).
The problem comes because I'm up in new england and the temps are starting to drop. SPI said spraying the epoxy was fine, but i'm going to be using z-chrome all-u-need poly, and they were not as confident in their product being used slightly outside of it's temperature range. The spec sheet says temp should be between 70 and 78 (such a narrow band). But temps here are looking to be mid 60's or so.
Do you guys think there will be a problem? It would be a real pain to get the car to a heated space.

also, the guy i spoke to at clausen didn't think any more primer over their all-u-need was necessary, but he was also trying to market the product as the one stop shop for priming. Should i still plan on wrapping the poly in epoxy?
sorry for all the Q's, first time painting a car and am tryign to avoid too many issues

[Alchemist]

Hi Danny,

Epoxy primers become stagnant (will not cure- even if catalyzed) if ambient temps are 55 degrees or below. Your metal body panels will be lower in temperature than the ambient temperature. Something to keep in mind if you decide to paint at lower than preferred ambient temp. I've had to do this many times during my shop days. I would suggest you get an infra red heating lamp if you don't have one already. You will be putting this good use and makes for a good investment.

I have this one for home use:
http://yhst-13811118617756.stores.yahoo.net/srpocusy.html

You can paint a section of your car and then bake it dry, using this initial application of epoxy primer as your foundtion. Just remember that you will need a minimum DFT (dry film thickness) which every primer product must have in order to meet performance specs.

You can paint a door then bake dry. On another day paint a fender etc., I'm sure you get the idea. If you're curing the painted part with this type of heat lamp I like to keep the heat lamp a "Minimum" of 3 feet away from the part otherwise you'll burn the paint!!

You can also use the heat lamp as a "heater" keeping the part warm enough to paint and keep moisture away during the winter months. You can do this by keeping the heater aimed at the part approximately 4-5 feet away - you would have to do a test initially by positioning the heat lamp, waiting approximately 10-15 minutes then feeling how warm the panel is.

I'm a little "detail crazy" and I actually measure the temperature of the panel I'm painting using a infra red thermometer. I purchased this product from Harbor Freight. I know it's not "surgically accurate" but give or take a couple of degrees - it works for me!
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96451

Here's an example; I've hung the door the same way as though it were mounted on the car. I place the heat lamp about 5 feet away from the door. I wait about 10-15 minutes and come out and check the door panel temp with the infra-red gun. I prefer to have the panel at 70 degrees because in general, all the paint manufacturers seem to hover around the 70 degree temp range when doing their testing.

anyway, hope this helps you on your way to getting your car primed and ready.

thanks,

Alchemist

[dannyho]

thanks for the reply. I'm going to try and track down one of those heaters today if I can. The guy at SPI said temperature wasn't an issue for their epoxy, but better safe than sorry.
still, do you think the extra coats of epoxy over the all-u-need are necessary? If it's anything but a useless step I'll still do it, but I'm just not sure

[Alchemist]

HI Danny,

First, I'm concerned that the person told you that temperature isn't an issue with Epoxy - that is completely incorrect! Direct to metal 2-part (catalyzed) epoxy primers can take up to 7 days or more to fully cure at 70-75 degress ambient temperatures. You start applying the EP at ambient temps lower than this and your panels are even at lower temps, the epoxy becomes stagnant (won't cure), it will congeal. This will cause problems if you apply your poly primer over it. Usually shrinkage will occur but this would be the least of your concerns.

I'm not familiar with this "all-u-need poly primer". Is it a "poly-urethane or poly-ester" base primer used as a surfacer for heavy filling? What is it's purpose please? Is there a website link please?

To seal the metal surface requires a certain amount of Dry Film Thickness (DFT). Every product has a minimum DFT requirement to be able to perform as advertised. If you merely apply one coat (which is the mistake most hobbyists make) of epoxy primer you haven't met the minimum DFT and will still allow moisture penetration. Each manufacturer will list this info on the product bulletin sheet which I would highly suggest you obtain for every product you are considering to use. It's a good idea to know what you have and what you can and cannot do before you go ahead and find out that you should not have done that!

To apply more EP over the "poly-primer" isn't necessary if you correctly applied the DTM EP which was to serve the purpose of sealing out the enviroment. Most, if not all primer surfacers are porous. If you applied the poly-primer directly over the metal intially, then it would be necessary to apply the multiple coats of epoxy primer over the poly-p to seal the pores and prevent moisture penetration if your purpose is to keep the body from oxidizing.

Please remember that epoxy primer is temp sensitive. To prove the point, I have taken left over EP and put in in the frig (not with food in it) and used it the next day after I left it out to bring it to room ambient temp - then applied it.

Hope this helps.

[dannyho]

hmm. Well you, my friend, are on a different level when it comes to understanding this, which is why I'll take your word and get it to a good temp first. I'm pretty positive it's polyester. basicly, a sprayable filler, it replaced the clausen z-chrome rust defender as i understand it. The application guide doesn't have much info about its contents, except that it's isocyanate free. and I couldnt find a link to the MSDS. at any rate here's the link to the app guide.
http://www.smartshoppersinc.com/automotive-refinishes/ClausenHelp.html
I don't expect what I'm doing to be perfect, but I just want something that wont peel or crack in a year or 2

[Alchemist]

Danny,

If I may suggest you call a few shops in your area and inquire if they have used this product. There may be a chance someone does and you can ask them more questions. Why not ask the store you purchased the primer at for a referral to an end user or shop?!

[SPEEDZONE]

I'm planning on painting the car soon. My plan is to get it bare metal, epoxy primer it, then after doing the more major work to be done, putting on the poly primer. I also had read that it was a good idea to spray epoxy over the poly again (I'm leaving out all the sanding steps in between).
The problem comes because I'm up in new england and the temps are starting to drop. SPI said spraying the epoxy was fine, but i'm going to be using z-chrome all-u-need poly, and they were not as confident in their product being used slightly outside of it's temperature range. The spec sheet says temp should be between 70 and 78 (such a narrow band). But temps here are looking to be mid 60's or so.
Do you guys think there will be a problem? It would be a real pain to get the car to a heated space.

also, the guy i spoke to at clausen didn't think any more primer over their all-u-need was necessary, but he was also trying to market the product as the one stop shop for priming. Should i still plan on wrapping the poly in epoxy?
sorry for all the Q's, first time painting a car and am tryign to avoid too many issues


Always seal polyester primer with epoxy or a 2k before topcoating. As stated, poly primer is porous and will absorb moisture, as well as the topcoat, to some degree.............