by "BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
Published 12/03/2017 at 14:42
by "BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
Published 12/03/2017 at 14:42
Tags: spit6
STARS: 11
I’ve painted the underside and chassis so I can bolt on the suspension and drop it down on its wheels for filling the outer panels. While I was there I did the interior too. Not exactly a stunning finish as there are a couple of things with pretty steep learning curves, but it’s good practice for the final visible panels :)
Heater pictured in a potentially futile attempt to heat the garage up enough that the 2k paint will actually cure in single-digit December weather. Does anyone know how long you need to leave your average 2k paint to cure before you can gingerly bolt stuff on? I know it’s a good couple of months before you can polish it properly...
"crowmolly" (crowmolly)
12/03/2017 at 15:07, STARS: 1
Well, what did you spray and what do the paint tech sheets say? How did you prep the substrate? Is that epoxy, high build, single stage, base coat?
As an example, Barry @ SPI says if you can’t keep the metal above 65* don’t bother spraying.
Also, I’m assuming you didn’t do this, but just as a reminder don’t ever spray with an open flame nearby. Can be a one way ticket to boom town.
"Rust and Dust - Oppositelock Forever" (rustanddust)
12/03/2017 at 15:09, STARS: 1
Looks good, congratulations!
What’s the temperature in the garage, and what speed reducers/catalysts did you use?
There should be some guidance on the can, if not look up the product line through Google.
"BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
12/03/2017 at 16:09, STARS: 0
Thanks!
Can’s not a great use. Only info on there is 4:1 hardener ratio and a lot of warnings.
Spec sheet is helpful though. 24h to assembly at 20c. Garage is at 11c heated which is a bugger (although 14c locally above the heater).
"BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
12/03/2017 at 16:32, STARS: 0
It’s Mipa 2-pack epoxy. 2 coats of high build primer, 2 coats of colour and 2 coats of clear on the underside (replacement paint I bought was gloss rather than base, so no clear on the interior...).
Tech sheets specify a 24h window until it’s safe to assemble at 20 deg c, but not a chance in hell it’s near that. It’s single digits out, and my garage is uninsulated. Managed to heat it up to about room temperature for the spraying itself (2 coats a day to allow for the solvent to dissipate before heating again).
Can basically maintain 11 deg c in the garage at the moment...
"BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
12/03/2017 at 17:18, STARS: 1
Oh, and I managed to avoid boom town ;) did that with a pool of what turned out to be petrol the other day and it would appear I’ve learnt my lesson...
"ITA97, now with more Jag @ opposite-lock.com" (ita97)
12/03/2017 at 19:01, STARS: 1
I srayed my car with a 2k single stage urethane in April in El Paso. Even with temperatures close to 90 in the garage during the day, it took a couple of weeks before it didn’t feel soft to the touch. On 2k paints, those handling times are usually on an assumption with the paint baking in an oven at 140 degrees for at least a of couple of hours.
"crowmolly" (crowmolly)
12/03/2017 at 20:22, STARS: 0
I’ll see if I can find the tech sheets for that stuff to look them over. For what it’s worth I’d bet that the curing process slows to a crawl around 10c. Checked my PPG stuff and they say that crosslinking and curing stops at 15-16c.
What order did you spray the stuff in, too? If it was colder between coats you may have issues.
"BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
12/04/2017 at 05:37, STARS: 0
Thanks man :) yeah I’ve done a fair bit of looking for tech sheets with a little more detail, but I think as the paint itself is German (and a lot of the data is in German) it’s tricky to find anything more than the basics.
Yeah I’ve been reading and a couple of numbers between 10 and 15 deg c have been thrown around for when cross-linking stops. Did another check and the air temp locally above the heater gets to about 30 deg c, with metal temp probably closer to 20, so the area directly above the heater is probably still functioning well.
I think current plan is to spend 48h of actual heating (over the course of a number of days) locally in the areas that I need to be strong enough to bolt stuff to so I can get moving on the next steps. Then, in the (probably weeks) of filler work I can hopefully let the other stuff cure at a far slower rate.
It was absolutely colder between coats which I was aware could produce issues. The order was 2x epoxy primer (day 1), 2x colour coat (day 2) and 2x gloss (day 3).
I was very cautious with flash times between coats to try and prevent issues. Spec sheet stated 8-10 minutes but I was leaving more like 45 between coats to ensure enough of the solvents worked their way out before laying on the next coat, and the 24 hours between each type of layer should hopefully be enough to prevent issues there. So far it seems to have held up :)
"BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
12/04/2017 at 05:48, STARS: 0
Luckily with this 2k the spec sheet states cure times at both 20 deg c and when baked at 140 so I can at least make a comparison :)
I’m hoping the faster hardener I got will help the cure in cold weather. A couple of weeks will be a big dent into getting it sorted by March!
"crowmolly" (crowmolly)
12/04/2017 at 11:43, STARS: 0
How was your ventilation? Did you have a fan constantly going for a while?
A possible problem is the temperature between coats. If the curing process stopped due to it being too cold, 45 minutes between coats won’t be enough and neither will 24h between layers. There will be trapped solvent.
Might be worth getting some heat lamps and letting them point at the areas you are worried about.
"davedave1111" (davedave1111)
12/04/2017 at 14:15, STARS: 0
Is another heater any use to you?
Free if you want it, but it’s in N London.
"davedave1111" (davedave1111)
12/04/2017 at 14:21, STARS: 0
If I can make a suggestion about dealing with variable cure times, spray up a spare sheet of metal the same way as soon as possible*. Then you have a test surface to check hardness on.
*Well, fairly soon, anyway. A couple of days’ margin won’t hurt.
"BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
12/04/2017 at 17:54, STARS: 1
Ventilation probably wasn’t particularly great while actually spraying, but plenty inbetween coats.
Found out that cross-linking stops at about 12 deg c so heating the garage up to 11 deg c will do diddly squat. So, I’m going for a localised 30 deg c above a pair of heaters at the front and rear and timing that for the actual curing of the areas I’ll be bolting to. That way I can heat the rest over a few weeks while I’m doing the filler.
Solvent trapped between the coats was a concern, hence the 45 minute flash-off time for the solvent to escape (spec sheet says 8-10 minutes, no minimum temperature stated).
There’s a definite possibility that it wasn’t enough, but the heated areas aren’t showing any sign of trapped solvent so far so fingers crossed!
Really, I’d leave this all to the summer but the europpomeet is looming in March so I’ve got to get cracking ;)
"BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
12/04/2017 at 17:58, STARS: 1
Thanks for the offer man :) if I didn’t already have one I’d be snapping that up ;)
I’ve worked out a way with two convection heaters beneath the front and rear suspension mounting points which heat them to ~30 deg c locally. They’ve been on for 12h and will be staying on for a further 24h just in case.
That way I can bolt the suspension on and get cracking with the filling while the rest cures over however long it takes to finish the filler work :)
"BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
12/04/2017 at 17:59, STARS: 0
Man’s a genius! Even if it’s a day or so behind I can still subject a test piece to the same conditions and check how hard it is.
Definitely preferable to pushing the boundaries with the paint on the car :)
"crowmolly" (crowmolly)
12/05/2017 at 09:54, STARS: 0
I feel ya. I have two projects on hold until the spring as it’s too cold to spray in an underheated speace, and the big heaters are an explosion risk.
I’m not sure if you can rent large heaters from an equipment place in your area- might be worth it to boost the garage temp overall for a day or so.
Also, check the spec sheets for your filler. A lot of them don’t work well under 15c and it can lead to shrinking and failure later on.
"BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
12/05/2017 at 16:41, STARS: 0
Yeah we’ve got a propane heater which got it to ~25 deg c air temp, but the £60 bottle of gas lasted maybe 6 hours so it would be mighty expensive the whole time!
Bolted on some suspension parts today and the paint held up pretty well :) still definitely not fully hard yet as I can score it easier than I’d expect, but it’s definitely workable :)
Great catch with the filler. Would be heartbraking for it to crack after what will probably be weeks of work...
"crowmolly" (crowmolly)
12/05/2017 at 17:13, STARS: 0
Yeah, sometimes improper prep/work won’t show up right away. It’s after 6 months or so when the paint lifts or a door closing pops off flakes. Best to just take it slow and be accurate :)
"davedave1111" (davedave1111)
12/06/2017 at 13:51, STARS: 1
“Thanks for the offer man :)“
That’s a very polite response to ‘clear out my crap for me so I don’t have to’ :)
"davedave1111" (davedave1111)
12/06/2017 at 13:58, STARS: 1
“Man’s a genius!”
Well, yes, but that was experience rather than sheer intellect :)