Body Undercoating

[Railroad]

I am taping up the edges and around the openings on my roadster body, prepping for undercoating.
Quick question, do I need to scuff the body, before coating?
I am using the Herculiner kit.

[FLPBFoot]

I pretty much followed the instructions on the Herculiner can. If I remember correctly it wants you to scuff with 40 grit and then use Xylene to wipe it all down before application. I used 60 grit sand paper in my palm sander and went over pretty much everything. It is sticky stuff.

[Papa]

You'll want to stay a couple of inches from the edges in any areas that your painter will be doing body work -- wheel wells in particular.

[GTBradley]

I don’t know about other painters, but mine suggested that I just leave the undercoating to him, as it was no big effort for him to apply it. You might check on your painter’s preference.

[Jeff Kleiner]

Just knock off any loose stuff and as Papa Dave said please stay back a couple of inches from openings, especially the wheelwells. I've used both Herculiner and Duplicolor Bed Armor. Bed Armor is my preference because cleans up with soap & water whereas Herculiner requires Xylene. Once they're cured you really can't tell the difference. Next one I have to do (I'd be perfectly happy to never do another) will get spray on undercoating.

Jeff

[Railroad]

Thanks for the tips and advise. I will put some paper on my DA and go to work.

[rich grsc]

Have you looked at the underside of the body? It's already ruff, it's unfinished fiberglass. There is no chance the undercoat will come off. I hit mine with an air hose to blow off the dust, then coated it. It's not coming off, unless you grind it off.

[Jeff Kleiner]

Have you looked at the underside of the body? It's already ruff, it's unfinished fiberglass. There is no chance the undercoat will come off. I hit mine with an air hose to blow off the dust, then coated it. It's not coming off, unless you grind it off.

Rich is exactly right. Once cured it is a (insert your derogatory swear word or phrase here) to remove, even by grinding. That's why I tell guys to hold it back from wheel openings or other areas that will be getting worked on during the bodywork process.

Jeff

[Ray]

I just rolled the body over and rolled the Herculiner on.....undercoat3.jpgundercoat2.jpgundercoat1.jpg

Used painters tape to keep it away from the edges.

Ray

[Railroad]

Those pics look familiar. I have just about everything taped up. I might have come off the edge a little more than what is pictured, wider tape.
I have not had a chance to sand anything. I am comfortable, having it dry and clean.
Thanks,

[jrcuz]

I plan on driving in gel coat probably a couple of years. I hope to have Jeff Kleiner do the body and paint. He won't be happy with me, I finished undercoating with Duplicolor bed armor 2-3 weeks ago and did it up to all edges. I guess I'm in trouble.
JR

[daltmcintyre]

Can either the Duplicolor or Herculiner be tinted or painted after it’s cured?

[edwardb]

Can either the Duplicolor or Herculiner be tinted or painted after it’s cured?

I don't know the direct answer to your question. But if you want something other than black (obviously sounds like you do...) take a look at the U-POL Raptor products. They have a tintable version with many colors offered. It's a 2-part spray on urethane product that I just finished using in my Coupe build. My use was just the standard black. But I'm very impressed with the product and the results are much better looking and far more durable than either Duplicolor or Herculiner. They also have a brush on version, but can't give any details or recommendation since mine was sprayed. My post with details here: https://thefactoryfiveforum.com/show...l=1#post382132.

[Railroad]

I finished the under coating on the body yesterday. A few tips, for using Herculiner. I did not sand the bottom of the fiberglass. I do not feel taping the edges is needed. You can brush a good line with the Herculiner. I did buy and use a drill operated paint stirrer. After brushing the tight places and edges the provided roller works very well. I did not try to get the total thickness on the first coat. I bought 2 plastic disposable paint pans, the small ones, worked great. Used 2, because I had a helper.
The particles stay suspended pretty good. I did not have to stir again, until second coat.
Wear rubber gloves, have some rags at hand, buy xylene or xylol, small can sufficient for this job.
I did wipe down the fender lip filler and general areas with a xylene rag.
I put the brush and roller in the fridge, after the first coat and went to lunch. An hour and half later the liner is tacky, but not wet. Time for second coat. I used the roller for this. I made sure, I did not see any red or fiberglass cloth pattern. I put a good coat in each fender area. Herculiner cautions against, mudding it on. Apparently it can or will crack, understandable. Herculiner does come in gray, hmmm?
It is pretty slow drying, open air, 88 degrees, some light wind, not in direct sunlight.
I would use it again. Just for consideration, I think you could use this without stirring to get a non particle finish. Read the instructions, there are some definite DO NOTS. The 1 gallon will probably do 2 roadster bodies.
Hope this helps those like me, who were very undecided on this job.