Howden Roots 2500 Series WHISPAIR MAX, Installation, Operation And Maintenance Manual

ISRB

 2005 GEA 20260

Page 19 of 24

Coating General 

Procedures for application are for one coat, but when 

multiple coats are to be applied, EACH coat must be 

completely cured per CURE procedure described 

following, before applying the next coat. 

Coating Application 

See notes on can concerning ventilation and 

inflammability.  
Each layer of coating should be applied as evenly as 

possible. Note directions on the curing of each 

coating layer applied before applying subsequent 

coats. 
The best distance of spray can nozzle to surface 

being coated is 8” to 12”. Try to maintain this distance 

wherever space conditions allow it. 

Coating Cure 

This procedure is for EACH coat. When multiple 

coats are to be applied, this curing procedure must 

be used on EACH coat before the next coat is 

applied. Keep coated parts clean during curing. 
Note that coated parts may feel dry or “tack free” 

after a few minutes, but the coat will not have the 

CURE that is required. 

Curing Procedures 

Alternate #1 

Let set for 1-1/2 hours, minimum, at normal room 

temperature (not less than 70°F). 
**Abradable coating applied to impellers is Slip Plate 

#3 as manufactured by Superior Graphite Co. For a 

material safety data sheet, go to www.slipplate.com. 

Study material safety data sheet before working with 

Slip Plate #3. 

Alternate #2 

Where ambient, and coated metal temperatures, are 

not at least 70°F, allow each coat to cure at least 

overnight in shop ambient (not warehouse or 

outdoors). 

Alternate #3 

Cure in oven, or by other source of even heat (not 

flame), for 10 minutes, minimum, at a temperature of 

310°F ±10. 

Alternate #4 

Cure in oven, or by other source of even heat (not 

flame), for one-half hour, minimum, at a temperature 

of 200°F ±10°. 

Check for Rotation 

Finish blower build up if not completely assembled 

when coated. In some instances, it is possible that 

clearances will be closed by coating to the extent that 

some surfaces touch. This is all right because the 

coating will wear (abrade) off as required. However, 

the blower may be hard to turn initially as a result. 

Turn over by hand until the running is free. Do not try 

to free up the blower by coupled or belted drive, and 

do not try to spin the rotors with shop air. Do not 

attempt to use any kind of solvent or cleaner to 

partially remove, coating – as this could ruin all of the 

coating. If necessary, coating can be scraped for 

such partial removal. 

Complete Removal of Coating 

This is for complete removal (to bare metal) of 

coating and may require some blower disassembly 

(depending on blower size and accessibility) for 

access to the coated parts and any overspray. Apply 

removal fluid liberally with a clean, “soaked” rag. 

Vigorously rubbing with this rag and scraping of the 

softened coating is required to clean surfaces down 

to bare metal, the amount of effort required will vary, 

depending upon the solvent used. Some are more 

effective than others. Protect surfaces, not coated, 

from rust. 

ISRB 2005 GEA 20260.indd   19

17/09/2015   12:53