Any information on spray insulation?

[Omniata]

Post mixing has been attempted by other firms and failed miserably.
The two components need to be intimately mixed prior to contact with the substrate or you get a sticky runny mess.
It takes about 5, maybe less, seconds to react before it gels, then foams. If it doesn't gel properly it's a nightmare to clean up and rectify.

You could use two hozelock garden sprayers connected to the foamseal nozzle/sprayer, but "adding solvents" is a tricky business.
You could use methylene chloride, but it would need to be less than a couple of percent or it would affect the mixing and "blowing" or "rise" of the foam mixture.

Best bet is to do it "warm" with the components heated to about 50°C, with no additional solvents. But you'd need someone stood there keeping the pressure up on the garden sprayers.

There are air pumps designed to pump from drums at high pressure, but again it's down to cost.

Single component foam was trialed many years ago, but for anything thick, over 25mm it doesn't cure properly as the moisture from the air can't penetrate deep enough.
It reacts or blows too quickly too as it's nearly 50% aerosol, wth an extremely low NCO content so it appears to have set relatively quickly, but doesn't complete for 24hrs.

The dual component systems fully react within about 15 minutes, dependent on mixing.

 

[Mee]

You can seal and use two pack, open the can and mix the two components together and just pour it in and let it expand.

 

[Omniata]

You can seal and use two pack, open the can and mix the two components together and just pour it in and let it expand.

I hope your not meaning to run them through a spray gun by this method?

 

[normspanners]

The two components need to be intimately mixed prior to contact with the substrate or you get a sticky runny mess.
It takes about 5, maybe less, seconds to react before it gels, then foams. If it doesn't gel properly it's a nightmare to clean up and rectify.

I bow to your knowledge sir it is just in the vid the gun seems to mix it at the nozzle .

 

[Omniata]

I bow to your knowledge sir it is just in the vid the gun seems to mix it at the nozzle .

as long as it's mixed before it leaves the nozzle it's fine, it's a right pain, the flow rates are ridiculous!
A lot of the pro guns have a gas purge and pin to push the residue out when you release the trigger.
The foamseal system has an "in nozzle" mixing system, hence the reason you need loads of nozzles, once set the only solvent that will shift it, DMF or dimethylformamide, will also partially dissolve the plastic.
It's not generally available now due to major environmental and health concerns.

The post mixing reference I have made, refers to mixing "after" it has left the nozzle, ie: where two fan nozzles point at the same point, it can be done, but maintaining the right distance throughout is a major skill in itself...

 

[Mee]

I hope your not meaning to run them through a spray gun by this method?

Not pourable.

 

[tracktoy]

this is an awesome thread, your knowledge on the subject is invaluable Omniata :-) , would garden sprayers produce enough pressure to spray the products properly, would a pressurised container system similar to the blasting pots work better?

 

[Brad93]

Quoted £16 pm. By the time you've stood there cut the boards, got wastage, pinned it up, taped the joints, rented a MEWP, taken a few days off work, that's not bad.

 

[Omniata]

Not pourable.

These mixtures aren't designed to be poured.
The gel time is way too fast as is the rise time, you can buy pourable mixes if you're lucky, but it won't be without difficulty.
You generally have special sliding spout mixing systems, I think relatively, they're worse than the spray systems.

this is an awesome thread, your knowledge on the subject is invaluable Omniata :-) , would garden sprayers produce enough pressure to spray the products properly, would a pressurised container system similar to the blasting pots work better?

Might be better with a high pressure pump drawing from a drum or canister, a bit safer than pressurising a cylinder containing components.
On the other hand, if the components are runny, like cooking oil, the pump up sprayers should be fine...
You would need someone pumping constantly though to keep the pressure up.

 

[Omniata]

Quoted £16 pm. By the time you've stood there cut the boards, got wastage, pinned it up, taped the joints, rented a MEWP, taken a few days off work, that's not bad.

That's a really good price!
What sized area?

 

[Wendelspanswick]

Quoted £16 pm. By the time you've stood there cut the boards, got wastage, pinned it up, taped the joints, rented a MEWP, taken a few days off work, that's not bad.

Is that plus vat? If it is that takes it up to £19.20 m2.
If you can claim the vat back then 100mm Cellotex is £7.20 m2 delivered to the door.

 

[Brad93]

Is that plus vat? If it is that takes it up to £19.20 m2.
If you can claim the vat back then 100mm Cellotex is £7.20 m2 delivered to the door.

Yes it may be but you haven't added labour, nor all the plywood and battening, adhesive, tape etc. Honestly, 168m the price of the foam works out cheaper than the boards.

 

[Brad93]

That's a really good price!
What sized area?

168m2.

Think that is plus VAT but can get that backz

 

[tracktoy]

Quoted £16 pm. By the time you've stood there cut the boards, got wastage, pinned it up, taped the joints, rented a MEWP, taken a few days off work, that's not bad.

who was that with?

 

[Brad93]

Can't remember now I wasn't here my dad got the quote.

 

[Parm]

I bow to your knowledge sir it is just in the vid the gun seems to mix it at the nozzle .

All commercial spray foam systems ive seen have the two ingredients in separate containers and are only ever mixed at the tip of the spray gun during application.

Some guns have a metal spriral thing as the mixer. This needs to be washed in dichloromethane.

Other ive seen have the plastic disposable spirals

It only ever make a runny mess if tis not mixed correctly as the two parts need to mix and chemically react to initiate the foaming process.

Should also highlight that the initiating chemical for the foaming process is an isocyante. Same stuff as used in 2K paints. Isocyantes are very very potent respiratory sensitizers

 

[tracktoy]

I keep looking at this foam

http://www.ebay.co.uk/itm/2-Part-Po...525827?hash=item3ad20329c3:g:kxQAAOSwjMJXBkMk

but am concerned by the "although closed cell and water-proof when set. It will absorb water when crushed"- if its closed cell how can it also absorb water?

 

[normspanners]

but am concerned by the "although closed cell and water-proof when set. It will absorb water when crushed"- if its closed cell how can it also absorb water?

Because a closed cell is just that----- closed ------sealed a bit like an empty pop bottle with the top on, but, crush and crack the pop bottle it can then leak water into it and contain some water through the cracks and then hold that water.

 

[Omniata]

All commercial spray foam systems ive seen have the two ingredients in separate containers and are only ever mixed at the tip of the spray gun during application.

Some guns have a metal spriral thing as the mixer. This needs to be washed in dichloromethane.

Other ive seen have the plastic disposable spirals

It only ever make a runny mess if tis not mixed correctly as the two parts need to mix and chemically react to initiate the foaming process.

Should also highlight that the initiating chemical for the foaming process is an isocyante. Same stuff as used in 2K paints. Isocyantes are very very potent respiratory sensitizers

The isocyanate is usually either part A or B, neat...

Because a closed cell is just that----- closed ------sealed a bit like an empty pop bottle with the top on, but, crush and crack the pop bottle it can then leak water into it and contain some water through the cracks and then hold that water.

As @normspanners says, crushing the foam "blows" the cells and makes them porous, however, it's entirely dependent on the "blowing agent", when R-141b was banned, the alternatives were twice the price, so manufacturers switched to adding 1/2 the blowing agent and extra water and a catalyst called DMDEE which cost a fortune but promoted the isocyanate water reaction to generate excess CO2 to blow the foam, so worked out overall at similar cost.
This resulted in a more closed cell structure than the blown structure created with R-141b...
The quality of the product was horrible in terms of use owing to the higher viscosity of the resin component compared to the isocyanate through lack of blowing agent.

 

[Parm]

The isocyanate is usually either part A or B, neat...



As @normspanners says, crushing the foam "blows" the cells and makes them porous, however, it's entirely dependent on the "blowing agent", when R-141b was banned, the alternatives were twice the price, so manufacturers switched to adding 1/2 the blowing agent and extra water and a catalyst called DMDEE which cost a fortune but promoted the isocyanate water reaction to generate excess CO2 to blow the foam, so worked out overall at similar cost.
This resulted in a more closed cell structure than the blown structure created with R-141b...
The quality of the product was horrible in terms of use owing to the higher viscosity of the resin component compared to the isocyanate through lack of blowing agent.

I can never remember if it's A or B but it's the activator component that initiates the reaction