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Topic Review (Newest First)
05-05-2013 06:14 PM
John long
Originally Posted by Lizer View Post
Does the SEM guidecoat spray in a fan pattern?
Josh, the SEM guide coat is basicaly pigment without filler. I use it regularly and it does work way better than spray paint and/or spray primer because it does not fill your sand paper. The powder very well may be better but the SEM is far better than paint. When I repainted my doors this spring I blocked the SPI black epoxy. I used white spray can laquer for guide coat and was wishing I had a can of light guide coat but my local store only had the black.

You will enjoy it if use it I am sure.

Yes it does have a pattern spray nozzle.

John L
05-05-2013 09:09 AM
Irelands child
Originally Posted by Lizer View Post
Does the SEM guidecoat spray in a fan pattern?
Yes - or at least the can's I've had did. Ya gotta remember, if the corporate finance guy can save a penny a case, things change

Brian - I've seen that acetylene trick used, but have never tried it - remember with some of us being overly mature, CRS goes hand in hand, so had forgotten.
05-05-2013 09:09 AM
geezer69 my buddy uses primer for glide coat. just uses dark over light or the other way around. its cheap and works fine. ive helped him many times and his paint jobs are awesome ! i sure as heck dont know much but he does so i thought id mention it here.
05-05-2013 09:02 AM
Lizer Does the SEM guidecoat spray in a fan pattern?
05-05-2013 08:13 AM
MARTINSR I am with you, I LOATH big corporations and chains believe me, I VERY rarely go into any chain when I have a local store or restaurant to give my money to.

But this 3m guide coat is SOOOOOOOO good, it is SOOOOO much better than spray paint you can't believe it. It covers EVERY square inch you want it, with a very fine dust going in very small scratches, it is well worth the money if you ask me.

There are alternatives, just yesterday at a swap meet I was having a long chat with one of my mentors from 35 years ago, one of my very valued mentors (and I tell him every time I see him) and he told me how he had begun to use soot from the torch for guide coat! He fires it up with just the acy on low and waves the torch on the panel putting soot all over it. He then wipes it all over with a rag and it goes in all the scratches and it's his guide coat. He told me how he found it by mistake after he welded a missed crack and then while sanding the area WHAM there were all the scratches. Never done it but it may be an alternative to the 3M stuff.

I am stubborn as heck when it comes to giving money to someone I don't like, I really respect your opinion on not giving money to 3m, believe me I do, but damn it if it's going to make my job easier and better sometimes I will just bite my lip and do it.

05-05-2013 07:55 AM
Irelands child Professionally, I would use the dry stuff, but being an amateur, use SEM guide coat, and purchased really cheap at a swap meet from a guy that always has a bunch. I dislike giving 3m any more of my hard earned dollars then necessary - even for their $$$ tape which doesn't seem as good as it was.
05-05-2013 07:38 AM
MARTINSR It lasts a long long time, get some dry you will never go back to spray paint again.

05-05-2013 06:59 AM
Originally Posted by mr4speed View Post
NO water (wet sanding) will not touch the dry guidecoat only sanding it off will get rid of it. If you are using the old flat black spray paint technique, trust me hands down the powder works and shows much more because it gets into every crevice there is.
This is what I heard too.dry is way better than spray can guide coat,so I went down and got some but when checking out it cost so much I left it there and ended up cursing 3-M again heck with my luck I'd drop it and dump it all over the floor...Isnt it just powderd charcoal?
05-04-2013 08:25 PM
Lizer I've been spraying SPI for the last 3 years, and it's the only thing I've ever sprayed (besides the Slick Sand). The Slick Sand is already blocked nearly off with 220. I think it sands like butter once I break through the crust with 120. Your suggestion isn't really any different than what's already been talked about here or what I've discussed with Barry, and it's what I'll be doing. Two coats of epoxy, wet sand to 600. I get little to no peel when I spray the epoxy so it will be easy sanding smooth. This is actually more convenient for me because I can just shoot the panels outside and if I get trash on them it will be sanded out.
05-04-2013 08:26 AM
Originally Posted by Lizer View Post
I'm a scientist, not a professional body man. And I've already been through 8 years of school.
Does that mean you cant learn anything else???? I learned the HARD way about these primers and blocking also..8 yrs is nothing..As much as you gonna hate hearing this: This is what I would do at this point...get a long stiff block and 80 grit and block all that poly off leaving it in the waves but nothing left where it isnt needed...spray two coats of SPI epoxy and block that with 180 dry then two more coats blocked out with a long rubber block 400 wet....then 600 ...
something else that poly primer does well is chip real be extra sure theres none at the edges like your jambs and wheel openings...
Since your not a pro I'll asume that your doing this for fun and enjoyment not to mention a love of old cars..Theres nothing fun about blocking so why make it harder than it needs to be you can block that off of there in no time and make things much more enjoyable using SPI and it'll last....
05-04-2013 07:47 AM
Lizer I'm a scientist, not a professional body man. And I've already been through 8 years of school.
05-04-2013 07:41 AM
Originally Posted by Lizer View Post
I went out and started the other fender with this (it's one of the few panels with 2k and not poly) and it was SO much faster needless to say. The paper cuts better, faster, longer. The problem is I can't see the scratches very well when doing it wet.
I wont sand anything without a guide coat,not even bondo..Use a guidecoat from start to finish...Now you know why I hate poly primers especially slick sand and feather fill..The ONLY thing they do well is HEAVY building and suck up water. If a panel or a whole car is so wavey it needs to be built up so much a 2k cant fill it ,HOLY crap someone needs to go back to school most oF the time an epoxy like SPI will do anything we need as far as building I usually go through about 2 gal (4sprayable) of epoxy to 1qt of 2k...using SPI of coarse...
Poly primers(spray bondo) really just make more work for you when you think about. lets say you have some waves and you want them filled so you spray the whole panel ,you have to block off everything else what a waste of time and material, mosy guys start off doing it then give up and just sand untill its straight ,leaving a massive amount of primer still on that panel because it sands so hard...You guys that are using and actually like these poly primers are still young and probably NEED to work of all that extra testosterone But us older bulls ,we like to make life EZer and walk down that hill and do'em ALL...
I just blocked out a hood I sprayed with two coats of epoxy and guide coated ,using 180 (dry) 20 min then I breezed over that (2min) with 320 dry just to knock down the roughness of the 180 reprimed 2 coats of epoxy and its ready for 400 wet,then a quick 600...This car HAS to be perfect its going SPI black and if it takes an hour to finish block ,I probably have a hang over....Using a poly primer makes absolutly no sence to me at all. I do all my filling BEFORE primer with poly putty like EZ sand...BTW, when we used that poly primer we sanded it with 80 grit I cant even imagine sanding it with anything finer..
05-03-2013 04:56 PM
Originally Posted by 33Willys77 View Post
If this is just a base primer you are trying to sand, why go with such a fine grit? For a full / big job - do your bodywork, ruff it in down to 80, prime it, block it straight with 80, prime it, block once more with 180, final prime and sand it with 400. Then seal it and paint (wet on wet).
the 600 was only because I was doing metallic, but was not considering that it is a moot point when I'm putting sealer over it anyways.

What I'm going to end up doing is final block with 220 as I've done, two coats epoxy, then wet sand with 600. I won't be able to put paint on wet on wet.
05-03-2013 10:17 AM
33Willys77 If this is just a base primer you are trying to sand, why go with such a fine grit? For a full / big job - do your bodywork, ruff it in down to 80, prime it, block it straight with 80, prime it, block once more with 180, final prime and sand it with 400. Then seal it and paint (wet on wet).
05-03-2013 05:27 AM
Originally Posted by John long View Post
Of course you are correct about any moisture causing major issues if it got trapped. Have you considered dry sanding it with a coarser grit and priming with 2 coats of SPI Epoxy and then wet sanding that with 400-600? Most epoxies do not sand well but I used SPI Epoxy when I repainted my doors and then blocked them with 400 and a guide coat. It really worked well.

My fear would be first that it will take forever to dry sand with 400. Secondly, I am not sure you can keep it clean enough not to get nib scratches in it. I would want to do my final sanding wet even if it meant using a 2k or epoxy primer for final prep. As I already mentioned I am not the professional here but I certainly have experienced the situation you are in.

I painted a 47 ford in 1978 with Eliminator which was one of the eariest polyester primers. I know I wet sanded it. It is in the shop now getting repainted. The paint I put on it only lasted 45 years. Obviously the moisture did have plenty of time to escape.

John L
John, I agree 7 billion percent. I was laying in bed thinking of a way I could wet sand this which really ended up with shooting full epoxy, and then thinking how ridiculously long it would take me to do all of it, and how much paper it would use.
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