Year: 2012

Projects: Essence Door Line

Client: Milgard Manufacturing Inc. - Windows & Doors

Category: Engineering, Architecture

My Role: The Essence Series® door project requires a sealant to connect real fir wood and fiberglass panels together. Under the research & development engineers and manufacturing team, the top three sealant choices were narrowed down and analyzed using structural shear and compression tests I developed and performed. In addition to the structural durability, other material requirements included eco-friendly chemistry, hazardous precautions, cost, and manufacturing compatibility.


Hot-melt Sealant Comparison

To select the most effective hot-melt sealant, I engineered an experiment using the testing lab and manufacturing floor equipment available to scientifically show which of the three top advertised sealants works best joining wood and fiberglass components as part of a new door project.








Compression Test

Shear Test


Experiment Procedures

Step 1

Evenly apply hot-melt sealant in the wood panel alignment grooves, then let it set for 2 minutes (keep the timer running for step 5).


Step 9

Repeat steps 1 – 8 twice, two more rounds thru. But in step 1, wait 3 minutes. In the second round wait 4 minutes.

Step 2

Zero the force gauge and place the wood panel onto the fiberglass panel, then use the press to join the two panels together.

Step 8

Repeat steps 1 thru 7 twice, two more rounds thru. Afterward, move to step 9.

Step 7

Note the amount of pressure required to pull apart the panels.

Step 6

Zero the force gauge and pull on the hydraulic ram cylinder until the wood and fiberglass panels come apart.

Step 5

Check the timer, in the first round wait 6 minutes before going to step 6. In second round wait 15 minutes. In third round wait 30 minutes.

Step 3

Note the time and amount of pressure it takes to fully press down/ bottom out the wood on the fiberglass panel.

Step 4

After panels are bonded note the following:

• Did the wood bounce back or stay in place? Measure height.

• How secure is the wood on the fiberglass, any sliding movement?

• If there is any excess sealant, how difficult is it to clean off panels or press machinery?


H.B. Fuller HL-5201

Dow Corning Instaglaze III

Schnee-Morehead SM2700

Results: H.B. Fuller HL-5201

Observations: From the data noticed small trend of when glue’s open time entended the higher compression needed, Low cohesive strength, material already set after shear apart. The HL-5201 sealant bonds to either the wood or fiberglass panel; leaving residue only on one surface.

Results: Dow Corning Instaglaze III

Observations: Compression unchanged between 2-4 minutes due to chemical properties of 15 minutes open time, After joining panels together and waiting 6-30 minutes the shear force to tear apart panels averages 20.78 psi -waiting 60 minutes the force only 24.10 psi, High initial cohesive stength. The DOW IGIII sealant remained intact to both the wood and fiberglass panels after seperated.

Results: Schnee-Morehead SM2700

Observations: High strength to compress after 2 minutes, Bonding strength still same between 2 - 4 minutes, After 60 minutes of curing big jump in adhesion, Low cohesive strength. The SM2700 sealant bonds to either the wood or fiberglass panel; leaving residue only on one surface


Best Effectiveness: Schnee-Morehead SM2700

The final selection was the Schnee-Morehead SM2700, rapid glaze sealant. Compared to the other sealants the initial green strength is great for our application requirements, it adds the lowest costs per panel, long twelve-month shelf life, high environmental friendly chemicals, and increased bonding strength over a longer period of time. It's versatility is a plus too and adheres to a variety of substrates including glass, PVC, fiberglass, wood, and various aluminum finishes, and the material creates a durable air and watertight seal, meeting AAMA standards and remaining flexible for the life of the assembly to which it is applied. Overall, the superior adhesion properties make this the desired sealant for our door panels.

SM2700 Properties (Typical Value)

Tensile Strength

239 psi

(1.65 N/mm2)

Shear Strength

170 psi

(1.17 N/mm2)

Open Time

5 min.

Shelf Life

12 months