Jotamastic 90 - 2 x Questions

[conor1n]

Evening all.

I'm doing a bit of a mega underside restoration on my SL at the moment.

Having blasted a nice bit of the rear underside. I am getting ready to apply some standard (non winter grade) Jotamastic 90.

Questions that aren't clear on the TDS.

1. Do you think I can use my 2.0mm lvlp primer gun for it ? Thin it 15%?

2. Do you guys I can spray some regular solvent basecoat on top or would I need an intermediate layer ?

I'm dubious enough about the weather really. Its 10 degrees here during the day but probably drops a bit over night.

Cheers
Conor

 

[ajlelectronics]

I'm dubious enough about the weather really. Its 10 degrees here during the day but probably drops a bit over night.

I couldn't get Kapci to go off after four days in 15C temperatures.

 

[conor1n]

I couldn't get Kapci to go off after four days in 15C temperatures.

OK.. what does the TDS say? I just checked the TDS For Jota 90 there and it says 5 degrees is OK with 30 hours to overcoat and 10 for 10 degrees. Be grand. Hope weather doesn't drop tonight... boo.

Also what did you do when you realised it wasn't going off?

 

[ajlelectronics]

OK.. what does the TDS say? I just checked the TDS For Jota 90 there and it says 5 degrees is OK with 30 hours to overcoat and 10 for 10 degrees. Be grand. Hope weather doesn't drop tonight... boo.

You should be fine then, I gather that Jotun has a winter variant.

Also what did you do when you realised it wasn't going off?

There was nothing I could do quickly. Eventually I used a chisel and scraped it all off, which was a pain because I had done an intricate area around the windscreen flange.

 

[conor1n]

You should be fine then, I gather that Jotun has a winter variant.




There was nothing I could do quickly. Eventually I used a chisel and scraped it all off, which was a pain because I had done an intricate area around the windscreen flange.

They do.. but I don't lmao. Momentary lapse. Should be grand. Fingers crossed.

 

[Dcal]

Yes, you should be able to spray it but 2mm might be a bit small, I use 2.5 and I need to overthin it (up to 20% thinners) or heat it, to get it to lay down nicely.

Give it a go, I find 90 sprays better than 87.
Both grades will go off, the winter grade just goes off faster.

 

[conor1n]

Yes, you should be able to spray it but 2mm might be a bit small, I use 2.5 and I need to overthin it (up to 20% thinners) or heat it, to get it to lay down nicely.

Give it a go, I find 90 sprays better than 87.
Both grades will go off, the winter grade just goes off faster.

Hmm thank you. Bit of a conundrum I find myself in then, with wanting to progress this over the hols.

Think I might just brush it on.. I'd be wary of over thinning it. What is the TDS max thin? 15%?

 

[pptom]

Fed up with I overspray and cleanup I put 5l on my last project car as repairs were progressing with a small foam roller from Screwfix / toolstation. They don't last long though with the solvents even with them meant to be solvent resistant (black ones were the best).
Disposable roller tray liners too so it's quick and easy. Plus a decent finish. I even used it on topside panels and high build primer covers it nicely - lots of my priming was this time of year though I did use wintergrade 'comp b' / activator

 

[conor1n]

Thanks everybody .. looks like I am going to be battling with the elements on this one.

If I was to order a paint gun, would a 3mm tip be better @Dcal or is 2.5mm fine?

I will see what the weather does in the next few days, and I might need to get some winter activator.

Thanks all

 

[Dcal]

I haven't tried a 3mm tip, they are not that easy to find.
The gun I use for thick paint came with 3 setups (1.4, 1.7 and 2.5)
It's similar to the one in the link below but with a plastic cup instead of the alloy one.
I've had it so long I forget where I got it, but think it was from a local motor factor.
I don't look after it that well but it still works just fine and I can't seem to kill it.

Pardon our interruption...

I just use the 2.5 setup as I've plenty of other guns.

If I was going to buy again I'd try the one below from Spraygundirect.
I can't recommend it, because I haven't use one, however it's cheap, you can get spares / other setups and its from a proper manufacturer.

2.5mm (AH1509014A) Archives - spray guns direct

www.spraygunsdirect.co.uk

If you have any sort of heat (infrared is perfect) the epoxy will go off, without, it just takes longer.

 

[Burdekin]

Thin it to 15 to 20% and heat to 30 to 40c and see how it sprays with the 2.0mm. Heating the paint will help it flow but also flash off and cure faster. If you can heat what you’re spraying up to 25c that will help also. Spraying in the cold is hard and takes more working out what works for you.

 

[Burdekin]

If you want to make life much easier this time of year go for Mipa epoxy with the fast hardener, you won’t need any thinners and sprays lovely. I sprayed it with a 1.4mm tip and it lays down super flat. It’s cheaper now as well: https://www.ebay.co.uk/itm/17411605...7Khr9wk3e6GUeKbCWsz6g7rpwRQx|tkp:BFBMoOnmp5Vj

 

[conor1n]

I haven't tried a 3mm tip, they are not that easy to find.
The gun I use for thick paint came with 3 setups (1.4, 1.7 and 2.5)
It's similar to the one in the link below but with a plastic cup instead of the alloy one.
I've had it so long I forget where I got it, but think it was from a local motor factor.
I don't look after it that well but it still works just fine and I can't seem to kill it.

Pardon our interruption...

I just use the 2.5 setup as I've plenty of other guns.

If I was going to buy again I'd try the one below from Spraygundirect.
I can't recommend it, because I haven't use one, however it's cheap, you can get spares / other setups and its from a proper manufacturer.

2.5mm (AH1509014A) Archives - spray guns direct

www.spraygunsdirect.co.uk

If you have any sort of heat (infrared is perfect) the epoxy will go off, without, it just takes longer.

Ok, fair enough. I will go with the 2.5mm

Oh and actually.. thanks for reminding me about that gun. I actually have that gun in a 1.8mm setup for primer.

I can't fault it at all really and I think I will buy another at 2.5mm for the epoxy.

I don't have infrared but a small PTC fan heater and an oil filled. I think I will get by with it... but also keep an eye on local classifieds and market place for a heater.

Do you rate the electric ignition kerosene type heaters for body work? If it's got cheap and cheerful.

Thin it to 15 to 20% and heat to 30 to 40c and see how it sprays with the 2.0mm. Heating the paint will help it flow but also flash off and cure faster. If you can heat what you’re spraying up to 25c that will help also. Spraying in the cold is hard and takes more working out what works for you.

Very good advice, thank you. I think I will wait for the 2.5mm tip, but I will definitely heat up everything before I get going.

I generaly use my PTC fan heater on the bench to heat the various containers and generally give them a shake to stir the liquid.

If you want to make life much easier this time of year go for Mipa epoxy with the fast hardener, you won’t need any thinners and sprays lovely. I sprayed it with a 1.4mm tip and it lays down super flat. It’s cheaper now as well: https://www.ebay.co.uk/itm/174116052926?hash=item288a201fbe:g:LXQAAOSw2Vdd5-L1&amdata=enc:AQAIAAAA4KqkltFV9ejEynk8SIl4Wnddv7UG4dpcACfs1lTBZhhUZpOxLdLpo2nq2KaLSycz3QIH/vDMGso4dLM/Lnh6ZJ3Df1K4spbdWZII+hHR1oJvNzMfkn8Og7stk5f1zQ4AU7nT5FScO5rh3F5ij7f04Rx/lWqw7cCmZLYCUX9/7q7XYEBURzhSx4RQNXjE+1lsEchp4CFzwijtrk5tNCQ3Cf5OKnyq/S0jOLvTt7TiTmOKgtUmPCCAk0wwk434h9NYPRJ1o1GeC3or3AJi7Khr9wk3e6GUeKbCWsz6g7rpwRQx|tkp:BFBMoOnmp5Vj

Interesting.... I will keep an eye on Mipa for other jobs, because it comes up from time to time.

 

[Burdekin]

Ok, fair enough. I will go with the 2.5mm

Oh and actually.. thanks for reminding me about that gun. I actually have that gun in a 1.8mm setup for primer.

I can't fault it at all really and I think I will buy another at 2.5mm for the epoxy.

I don't have infrared but a small PTC fan heater and an oil filled. I think I will get by with it... but also keep an eye on local classifieds and market place for a heater.

Do you rate the electric ignition kerosene type heaters for body work? If it's got cheap and cheerful.



Very good advice, thank you. I think I will wait for the 2.5mm tip, but I will definitely heat up everything before I get going.

I generaly use my PTC fan heater on the bench to heat the various containers and generally give them a shake to stir the liquid.



Interesting.... I will keep an eye on Mipa for other jobs, because it comes up from time to time.

You can also use a microwave or bucket of hot water.

 

[RaceDiagnostics]

Underside, why not brush it on?

 

[conor1n]

Underside, why not brush it on?

Very valid question. I'll tell you why....and I consider this a bad reason LMAO, I advance.

Because I don't want to see the brush strokes in final finish. And I think I'm going to go straight base coat over it.. so no high build primer.

If I was priming I would brush it on for sure.

I am going with Lesonal solvent base, hope it's OK over the mastic....

 

[badabec]

I rollered Jotun 87 in the engine bay and underneath. Looks like this..

 

[chrisg3103]

i brushed on when i did the underside, was a pain and took forever! ended up buying one of these things - https://www.ebay.co.uk/itm/31501984...uid=IUoauAtKSrO&widget_ver=artemis&media=COPY

Pressure pot sprayer, for the top coat, went on so easy. Ideal for upside down close quarters stuff as you don't have to worry about the pot going upside down, only mishap was a loose fitting that resulted in some rapid paint evacuation onto the drive.
Only downside is having to flush the paint tube, apart from that just like cleaning a normal gun

 

[Torqu-E-Cycles]

If you roller it as I intend to do apparently its extremely hard to sand? Although I'm sure a 240 da will flat it no problem?

 

[conor1n]

i brushed on when i did the underside, was a pain and took forever! ended up buying one of these things - https://www.ebay.co.uk/itm/31501984...uid=IUoauAtKSrO&widget_ver=artemis&media=COPY

Pressure pot sprayer, for the top coat, went on so easy. Ideal for upside down close quarters stuff as you don't have to worry about the pot going upside down, only mishap was a loose fitting that resulted in some rapid paint evacuation onto the drive.
Only downside is having to flush the paint tube, apart from that just like cleaning a normal gun

Cool - I think I will order one of those pots.. I've really been hoping to get a pressure pot as I am sure there will be issues painting tight spaces, such as strut towers etc.

I keep a dirty gallon of thinners around which will be great for flushing out. Then I would just run a cup full of clean thinners through it. I pride myself on my extremely miserly approach to cleaning implements.. I use only minimal amounts of fresh thinners LMAO

If you roller it as I intend to do apparently its extremely hard to sand? Although I'm sure a 240 da will flat it no problem?

Interesting. I can't see myself rolling it on tbh. I can just imagine I will be unlucky and buy a crap foam roller that just dissolves before my eyes.. that would boil my blood.