×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Spray or Brush Grade

Spray or Brush Grade

Spray or Brush Grade

(OP)
If properly formulated, is there an advantage to using spray or brush grade polyurethane coatings?  I understand that they both bond to existing coatings by mechanical and not chemical means.

I was informed that the spray grade is less viscous and because of the spray pressure that it bonds to the mechanical roughened adjacent surface better.  Is this correct?

thanks, Dik

RE: Spray or Brush Grade

I do not think there is any difference. The 2 part urethane coatings I use have different thinners, for brushing or spraying.

The primers bond to substrates by mechanical means, topcoats over primers have a time window where some chemical crosslinking is possible, after that it is strictly mechanical.

 The spray reducers simply allow for  evaporation between paint leaving the gun and arriving at the surface.

 The most common method I use for application, is the roll and tip method, where the paint is thinned to a spray consistency,then rolled onto the job,  tipped off once only with a high quality brush. This removes the bubbles intoduced by the roller and allows the paint film to stretch out into a high quality finish that looks as though it has been sprayed. It is important to tip only once and quickly as soon as the paint is rolled on or brush marks will be introduced into the finish.
B.E.

The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them.  Old professor

RE: Spray or Brush Grade

(OP)
Thanks...

Dik

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources