clear sealer

[truckdoctor]

Looking for advice and knowledge form experts here whether I can put Max Meyer 1.8410204 acrylic 2k sealer onto prepped cellulose/filler etc, and follow with cellulose primer and topcoat.
Many thanks

 

[langy]

My question would be why use a 2K sealer and then use celly primer ???

 

[steveo3002]

id stick with all one type...all 2k or all celly

 

[norsa]

as both above. What are you trying to seal?

 

[truckdoctor]

OK I'll try to explain a little, firstly though I'm not a professional painter, my experience is with cellulose from the late 70's, until recently I've not used paint much, obviously between then and now things have changed a great deal, and am looking for advice and help.
I've carried out localised repairs to rust to bottoms of wings and doors, welding in new metal and prepping with filler cellulose primer and topcoat to the whole panel. This has resulted in paint defects mostly where my repairs meet the old existing paint but also in some other random areas where the old paint was prepped to accept the new. These defects are sinking crazing and cracking. The car is over 40 years old and has had repairs and paint previously though I have no history or knowledge of what products have been used.
I'm hoping to apply a modern 2 pack paint(clear sealer) that wont affect what lies beneath over what is already there, hopefully to provide an impenetrable barrier as a good base for further paint, preferably cellulose.
I've just tried a two pack epoxy primer ( max 1855990 with 19569500) over fairly new cellulose in an attempt to provide a barrier and chose the incorrect product as although it went on fine over filled areas it melted the cellulose and wouldn't harden, this has subsequently been removed.

I see from American car shows on the TV they us a "sealer" under their paint, sometimes over rusted worn paint as a barrier to keep it's patina . Now I don't know what product they use but wonder if
maybe this clear sealer will do the job for me, anyone used it or recommend some other product?

 

[langy]

I hate to tell you this but doing what you propose is only gonna end in tears in my opinion, it really needs stripping back

 

[marlinspike]

I have next to no car spraying experience but it really doesn't sound a good idea to me. It also seems like quite a lot of work to do something that will probably have to be sorted out again later. I suppose it comes down to what the car is worth to you - financial and sentimental value. If it's a car that will appreciate or that you love, strip it all back and do it properly. I can't imagine 2k sealer is cheap, though, so you might as well do it properly, especially if you have the gear to spray 2k.

 

[steveo3002]

yeah it wont work..

the existing paint thats on there may soften and move etc with the sun ..as youve found out seeing cracks and sinkage marks

if you sealed it in with 2k it wont stop that underlaying paint shifting about so will continue to crack etc

all you can do is strip it back to metal

 

[truckdoctor]

Thanks for your replies, I've taken on board your comments and decided to strip back to bare metal/ filler. 60 grit is clogging up straight away so have ended up with a 100mm rotary wire brush rotated with a polishing machine at the slowest speed and it's coming off in lumps like sticky toffee. Just done the bottom half of a door and it's taken four hours, going to be at it a long time.
One thing puzzling to me is why the 2 pack melted the cellulose paint recently applied?

 

[norsa]

Sounds very much like its been done in part or in its entirity in synthetic enamel. Langy and Steveo will maybe agree. This being the case, it is a complete nightmare for every refinishing untill its gone.
Nick.

 

[marlinspike]

I have just stripped a cast iron fireplace. Started off with paint stripper but then used a Dronco coarse fleece on an angle grinder. Previously when removing rust on a car I've used a wire cup in a drill. Compared to that the Dronco fleece was streets ahead and took off thick gloss really easily and with no sparks either. Will be using them on the car next time. Weldequip sell them if you want to give them a try.

 

[Wendelspanswick]

I had good success with a two handed Skarsten (spelling?) Tungsten scraper to strip the crappy mix of paint that had been applied to my sons MGB GT over the years, found it worked best when the paint was warm, either park it in the sun or use a blow torch to gently warm the paint, you are not burning it off!

 

[ytre]

Be really careful of 2 pack and use the best breathing apparatus money can buy, a friend recently was diagnosed with cancer, after tests the one question the specialist asked" have you been using 2 pack".
Think its the hardener that's most dangerous.

 

[keithski122]

According to government website 2 pack paint can cause asthma and dermatitis but not cancer from the isocyanates.
http://www.hse.gov.uk/pubns/guidance/mr2.pdf

 

[langy]

Be really careful of 2 pack and use the best breathing apparatus money can buy, a friend recently was diagnosed with cancer, after tests the one question the specialist asked" have you been using 2 pack".
Think its the hardener that's most dangerous.

The only good thing to breathe is air

 

[truckdoctor]

x2

 

[truckdoctor]

Thanks for your help and advice so far.
A bit of a progress report and a question, stripped backed the door skins to bare metal to remove all the underlying defective products, prepped with epoxy and green TI ( rolled on) and found the paint superior to cellulose so would like to try 2 pack topcoat. The thing is, the door jams are fine with no defects and freshly painted in cellulose so can I apply the 2 pack topcoat directly on top after a rub down with 600 ?
Thanks

 

[marlinspike]

Wouldn't the cellulose react? Can you spray 2k primer over the rubbed down cellulose first? There are £20 smart guns on ebay if you only want to do small areas like the door jambs.

 

[richie00boy]

The cellulose is just as likely to react with 2k primer as with 2k topcoat. It would be better to remove it, although there is less solvent in 2k it can still affect cellulose.