Rokide coating troubleshooting

[pakalano]

Good day all,

We have recently started spraying Rokide MBA and A rod material on 303 stainless substrate. As the manufacturers' data suggests, we are running 2 bottles of acetylene on a manifold at 15psi thru a 2 stage regulator. We are unable to maintain the 60+ on the flowmeter that the system requires but for 1/2 a rod. The coatings are spraying out with a significant amount of spatter, not fine like they need to be, and the result after grinding is a 75Ra +-.; The coatings are very porous.
Upon speaking to some industry colleagues, they report having to run the acetylene pressure op to 20psi to obtain enough heat from the flame to produce fine coatings. We are not comfortable doing so as all safety standards do not recommend ever running over 15 psi.

Does anyone have some techniques or tips to help us troubleshoot what the issue could be?

[sprayloud]

Hey,

My ideas on the matter.
First, if you can not maintain acetylene at 60 your hose from system to gun might be too small in diameter.
If you can not maintain acetylene at 60 you should reduce oxygen accordingly. The ratio of fuel/oxygen is important.
Finally while the gun is in operation you should put on some really dark glasses and look at the air cap of the gun from the side. Rod should be visible but not extended from the gun too long or even inside for a few mm ( you should play with the rod feed for best results). This should help with the spatter and roughness.
I've never used rod just flexicord but i imagine it being similar

[pakalano]

Thank you for your response. We did find maintaining the gas level was not possible and experimented with lowering the oxygen pressure but the resulting coating is negatively affected by lack of heat. Were have paid particular attention to the rod and the air cap and have that point satisfied as per your description. We can control the spatter very well on the RK rods, but the AO rods are a challenge.
We found we may have a flow constriction in the gas connections that is contributing to our low flow. If we can increase that flow without using higher gas pressure we may be onto something!

Hey,

My ideas on the matter.
First, if you can not maintain acetylene at 60 your hose from system to gun might be too small in diameter.
If you can not maintain acetylene at 60 you should reduce oxygen accordingly. The ratio of fuel/oxygen is important.
Finally while the gun is in operation you should put on some really dark glasses and look at the air cap of the gun from the side. Rod should be visible but not extended from the gun too long or even inside for a few mm ( you should play with the rod feed for best results). This should help with the spatter and roughness.
I've never used rod just flexicord but i imagine it being similar
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