seasofcheese
New member
one more.. would you jet blast or vacuum and wipe down with thinner before applying paint?
advice needed on shot blasting interior of steel hull
- Thread starter seasofcheese
- Start date
rogerthebodger
Well-known member
I had a team of 4 doing the blasting and a team of 4, including, myself, cleaning up and painting. The clean up team used shoves and brushes to get most grit out and then vacuum out the remaining. We still found some left when we painted.
Have a look at some of the pics I posted. It is not a job I would do myself and would not like to do it again.
Get yourself a smallish compressor and an air needle gun to clean off and sections you may find later and for subsequent maintainance .
Have a look at some of the pics I posted. It is not a job I would do myself and would not like to do it again.
Get yourself a smallish compressor and an air needle gun to clean off and sections you may find later and for subsequent maintainance .
mersey
Member
seasofcheese
New member
it has been covered in other threads- rust converters are useless because of poor adhesion qualities
Pasarell
Well-known member
Sorry for the delay getting back to your questions.
Should have mentioned before it would be wise to pressure wash very thoroughly before blasting to remove as many contaminants as possible. Obviously need to do it in good time so the surface is completely dry before blasting.
Your comment about sprayed material penetrating better is, I'm afraid, wrong. Atomised paint will tend to go away from internal corners between the nozzle and substrate leaving a lower film thickness in the most vulnerable areas. It will also tend to bridge across small pits and holes as often found in welds rather than flowing into them. On outside corners the surface tension of the paint will draw it away from the corner, again leaving a thin film on the most vulnerable part. Stripe coating will help to overcome this as you can work the paint into all the edges and crevices then build the film with the full sprayed coat.
Intercure 200 is a good blast primer but what total dft do you intend to apply? I don't have a data sheet to hand but I seem to recall 2 issues:-
- It is only designed as a first coat so you may want to build the finish dft with something like Intershield 300
- It is not recommended for immersion so if there is likely to be sitting water in the bilge this may not be ideal.
Interfine 979 is definitely not suitable. It's fine as a finish coat but I assume most of your hull ill be covered by internal fit out, and that you will probably put something like foam insulation over the whole hull anyway.
What total dft do you plan to apply? I would want at least 300 microns and would probably go for 500. Do you have a dft gauge? If not cheap Chinese ones are on ebay for about £100 and there are often good Elcometer 345's being sold for £50 or so second hand. It would be a wise investment I think!
I would vacuum carefully and when all debris is removed wipe down with thinners. You will not get rid of every bit of debris unfortunately but important to be as careful as possible. Wipe down with a thinner that is compatible with your primer and ensure you use clean clotheswith each surface only used once. It is a common mistake to keep using dirty cloths and think you are doing some good when in fact only picking contaminants up from one place and depositing them in another.
Mersey: Seasofcheese has already answered but to expand a little. Rust converters are a very low grade way of preparing a steel surface where no other system is available. Blasting / needling / grinding will all remove the rust so nothing to convert. Even if corrosion is left on the surface a rust converter will almost certainly inhibit adhesion between first primer coat and substrate and will be a big step back from the blasted surface he starts with. A little flash rusting or gingering of the surface is not a problem for a modern blast primer especially if it contains zinc.
Should have mentioned before it would be wise to pressure wash very thoroughly before blasting to remove as many contaminants as possible. Obviously need to do it in good time so the surface is completely dry before blasting.
Your comment about sprayed material penetrating better is, I'm afraid, wrong. Atomised paint will tend to go away from internal corners between the nozzle and substrate leaving a lower film thickness in the most vulnerable areas. It will also tend to bridge across small pits and holes as often found in welds rather than flowing into them. On outside corners the surface tension of the paint will draw it away from the corner, again leaving a thin film on the most vulnerable part. Stripe coating will help to overcome this as you can work the paint into all the edges and crevices then build the film with the full sprayed coat.
Intercure 200 is a good blast primer but what total dft do you intend to apply? I don't have a data sheet to hand but I seem to recall 2 issues:-
- It is only designed as a first coat so you may want to build the finish dft with something like Intershield 300
- It is not recommended for immersion so if there is likely to be sitting water in the bilge this may not be ideal.
Interfine 979 is definitely not suitable. It's fine as a finish coat but I assume most of your hull ill be covered by internal fit out, and that you will probably put something like foam insulation over the whole hull anyway.
What total dft do you plan to apply? I would want at least 300 microns and would probably go for 500. Do you have a dft gauge? If not cheap Chinese ones are on ebay for about £100 and there are often good Elcometer 345's being sold for £50 or so second hand. It would be a wise investment I think!
I would vacuum carefully and when all debris is removed wipe down with thinners. You will not get rid of every bit of debris unfortunately but important to be as careful as possible. Wipe down with a thinner that is compatible with your primer and ensure you use clean clotheswith each surface only used once. It is a common mistake to keep using dirty cloths and think you are doing some good when in fact only picking contaminants up from one place and depositing them in another.
Mersey: Seasofcheese has already answered but to expand a little. Rust converters are a very low grade way of preparing a steel surface where no other system is available. Blasting / needling / grinding will all remove the rust so nothing to convert. Even if corrosion is left on the surface a rust converter will almost certainly inhibit adhesion between first primer coat and substrate and will be a big step back from the blasted surface he starts with. A little flash rusting or gingering of the surface is not a problem for a modern blast primer especially if it contains zinc.
wotayottie
New member
If £1500 is "expensive" now and you still have a hull of that size to fit out, then I would sell the hull right now. You have taken on a monster job and the fitting out is way more expensive than the hull itself.
Project like this you have to be practical and not a dreamer
Project like this you have to be practical and not a dreamer
dsw
Member
Had mine blasted with aqua glass then SigmaTCN440 sprayed on
And after 7 years no rust . 37ft x 13ft £700. (kent)
And after 7 years no rust . 37ft x 13ft £700. (kent)
ean_p
Well-known member
Can someone supply me with details of one of these please?
Pasarell
Well-known member
You can buy them in hobby shops or slightly bigger versions in places like Machine Mart. Be prepared for a very, very slow job and not very good results
ean_p
Well-known member
Thanks for the reply Pasarell
I've tried the 'hooded' spot blasters from machine Mart and found them very lacking..... just thought that those mentioned by KE above might be of a bit better quality as looking for a small unit for touch up maintenance to carry around with me, working on the idea that a reasonable sized air comp' can be found in most places. Best I've found so far is the portable unit from Redashe. I've a second hand one as new they are well into 4 figures!
I've tried the 'hooded' spot blasters from machine Mart and found them very lacking..... just thought that those mentioned by KE above might be of a bit better quality as looking for a small unit for touch up maintenance to carry around with me, working on the idea that a reasonable sized air comp' can be found in most places. Best I've found so far is the portable unit from Redashe. I've a second hand one as new they are well into 4 figures!
seasofcheese
New member
Thanks again Pasarell.
Would intercure 200 suit as first coat for immersed places and then immersion resistant paint on top?
Would intercure 200 suit as first coat for immersed places and then immersion resistant paint on top?
Pasarell
Well-known member
I believe it would but you would be better checking that with the International Technical Department. They should be very helpful
Mercado
N/A
hi
actually i don't know much about this that wax can prevent rust for long or not but hope that your plan should succeed and pay you back for what you have invested in it.
actually i don't know much about this that wax can prevent rust for long or not but hope that your plan should succeed and pay you back for what you have invested in it.
seasofcheese
New member
here's the update- irish contractor wasted two weeks of my time and j radford group came and grit blasted for £750.. brilliant quality.. had six friends to clean out the grit.. sprayed 40 litres of intercure 200. anyone interested in pics/ videos of the job http://www.tomice.tumblr.com/